Bio

Mike McGehee's primary research interests are developing new materials for smart windows and solar cells. He has taught courses on nanotechnology, nanocharacterization, organic semiconductors, polymer science and solar cells. He received his undergraduate degree in physics from Princeton University and his PhD degree in Materials Science from the University of California at Santa Barbara, where he did research on polymer lasers in the lab of Nobel Laureate Alan Heeger. He won the 2007 Materials Research Society Outstanding Young Investigator Award. He is a technical advisor to Next Energy, PLANT PV, and Sinovia and his former students have started more than ten companies.

Academic Appointments

Honors & Awards

  • Vance D. & Arlene C. Coffman Faculty Scholar, Vance D. & Arlene C. Coffman Faculty Scholar (2007)
  • Innovators Award, Mohr Davidow (2007)
  • Outstanding Young Investigator Award, MRS (2007)
  • Gilbreth Lecturer, National Academy of Engineering's National Meeting (2006)
  • Young Professor Award, Dupont (2001)
  • CAREER Award, National Science Foundation (2001)
  • New Faculty Award, Henry and Camille Dreyfus (2000)
  • Graduate Student Gold Medal Award, Materials Research Society (1999)

Professional Education

  • PhD, UC Santa Barbara, Materials Science (1999)
  • BA, Princeton, Physics (1994)

Contact

Links

2015-16 Courses

Stanford Advisees

All Publications

  • Reversible photo-induced trap formation in mixed-halide hybrid perovskites for photovoltaics CHEMICAL SCIENCE Hoke, E. T., Slotcavage, D. J., Dohner, E. R., Bowring, A. R., Karunadasa, H. I., McGehee, M. D. 2015; 6 (1): 613-617

    View details for DOI 10.1039/c4sc03141e

    View details for Web of Science ID 000345901600072

  • Semi-transparent perovskite solar cells for tandems with silicon and CIGS ENERGY & ENVIRONMENTAL SCIENCE Bailie, C. D., Christoforo, M. G., Mailoa, J. P., Bowring, A. R., Unger, E. L., Nguyen, W. H., Burschka, J., Pellet, N., Lee, J. Z., Graetzel, M., Noufi, R., Buonassisi, T., Salleo, A., McGehee, M. D. 2015; 8 (3): 956-963

    View details for DOI 10.1039/c4ee03322a

    View details for Web of Science ID 000352274600021

  • Hysteresis and transient behavior in current-voltage measurements of hybrid-perovskite absorber solar cells ENERGY & ENVIRONMENTAL SCIENCE Unger, E. L., Hoke, E. T., Bailie, C. D., NGUYEN, W. H., Bowring, A. R., Heumueller, T., Christoforo, M. G., McGehee, M. D. 2014; 7 (11): 3690-3698

    View details for DOI 10.1039/c4ee02465f

    View details for Web of Science ID 000343974700019

  • Characterization of the Polymer Energy Landscape in Polymer:Fullerene Bulk Heterojunctions with Pure and Mixed Phases JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Sweetnam, S., Graham, K. R., Ndjawa, G. O., Heumueller, T., Bartelt, J. A., Burke, T. M., Li, W., You, W., Amassian, A., McGehee, M. D. 2014; 136 (40): 14078-14088

    View details for DOI 10.1021/ja505463r

    View details for Web of Science ID 000343026700025

  • Reducing burn-in voltage loss in polymer solar cells by increasing the polymer crystallinity ENERGY & ENVIRONMENTAL SCIENCE Heumueller, T., Mateker, W. R., Sachs-Quintana, I. T., Vandewal, K., Bartelt, J. A., Burke, T. M., Ameri, T., Brabec, C. J., McGehee, M. D. 2014; 7 (9): 2974-2980

    View details for DOI 10.1039/c4ee01842g

    View details for Web of Science ID 000340450100015

  • Comparing the Device Physics and Morphology of Polymer Solar Cells Employing Fullerenes and Non-Fullerene Acceptors ADVANCED ENERGY MATERIALS Bloking, J. T., Giovenzana, T., Higgs, A. T., Ponec, A. J., Hoke, E. T., Vandewal, K., Ko, S., Bao, Z., Sellinger, A., McGehee, M. D. 2014; 4 (12)

    View details for DOI 10.1002/aenm.201301426

    View details for Web of Science ID 000341234600001

  • Enhancing the Hole-Conductivity of Spiro-OMeTAD without Oxygen or Lithium Salts by Using Spiro(TFSI)(2) in Perovskite and Dye-Sensitized Solar Cells JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Nguyen, W. H., Bailie, C. D., Unger, E. L., McGehee, M. D. 2014; 136 (31): 10996-11001

    Abstract

    2,2',7,7'-Tetrakis(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene (spiro-OMeTAD), the prevalent organic hole transport material used in solid-state dye-sensitized solar cells and perovskite-absorber solar cells, relies on an uncontrolled oxidative process to reach appreciable conductivity. This work presents the use of a dicationic salt of spiro-OMeTAD, named spiro(TFSI)2, as a facile means of controllably increasing the conductivity of spiro-OMeTAD up to 10(-3) S cm(-1) without relying on oxidation in air. Spiro(TFSI)2 enables the first demonstration of solid-state dye-sensitized solar cells fabricated and operated with the complete exclusion of oxygen after deposition of the sensitizer with higher and more reproducible device performance. Perovskite-absorber solar cells fabricated with spiro(TFSI)2 show improved operating stability in an inert atmosphere. Gaining control of the conductivity of the HTM in both dye-sensitized and perovskite-absorber solar cells in an inert atmosphere using spiro(TFSI)2 is an important step toward the commercialization of these technologies.

    View details for DOI 10.1021/ja504539w

    View details for Web of Science ID 000340079800035

  • Importance of the Donor:Fullerene Intermolecular Arrangement for High-Efficiency Organic Photovoltaics JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Graham, K. R., Cabanetos, C., Jahnke, J. P., Idso, M. N., El Labban, A., Ndjawa, G. O., Heumueller, T., Vandewal, K., Salleo, A., Chmelka, B. F., Amassian, A., Beaujuge, P. M., McGehee, M. D. 2014; 136 (27): 9608-9618

    Abstract

    The performance of organic photovoltaic (OPV) material systems are hypothesized to depend strongly on the intermolecular arrangements at the donor:fullerene interfaces. A review of some of the most efficient polymers utilized in polymer:fullerene PV devices, combined with an analysis of reported polymer donor materials wherein the same conjugated backbone was used with varying alkyl substituents, supports this hypothesis. Specifically, the literature shows that higher-performing donor-acceptor type polymers generally have acceptor moieties that are sterically accessible for interactions with the fullerene derivative, whereas the corresponding donor moieties tend to have branched alkyl substituents that sterically hinder interactions with the fullerene. To further explore the idea that the most beneficial polymer:fullerene arrangement involves the fullerene docking with the acceptor moiety, a family of benzo[1,2-b:4,5-b']dithiophene-thieno[3,4-c]pyrrole-4,6-dione polymers (PBDTTPD derivatives) was synthesized and tested in a variety of PV device types with vastly different aggregation states of the polymer. In agreement with our hypothesis, the PBDTTPD derivative with a more sterically accessible acceptor moiety and a more sterically hindered donor moiety shows the highest performance in bulk-heterojunction, bilayer, and low-polymer concentration PV devices where fullerene derivatives serve as the electron-accepting materials. Furthermore, external quantum efficiency measurements of the charge-transfer state and solid-state two-dimensional (2D) (13)C{(1)H} heteronuclear correlation (HETCOR) NMR analyses support that a specific polymer:fullerene arrangement is present for the highest performing PBDTTPD derivative, in which the fullerene is in closer proximity to the acceptor moiety of the polymer. This work demonstrates that the polymer:fullerene arrangement and resulting intermolecular interactions may be key factors in determining the performance of OPV material systems.

    View details for DOI 10.1021/ja502985g

    View details for Web of Science ID 000338980500018

  • Electron Barrier Formation at the Organic-Back Contact Interface is the First Step in Thermal Degradation of Polymer Solar Cells ADVANCED FUNCTIONAL MATERIALS Sachs-Quintana, I. T., Heumueller, T., Mateker, W. R., Orozco, D. E., Cheacharoen, R., Sweetnam, S., Brabec, C. J., McGehee, M. D. 2014; 24 (25): 3978-3985

    View details for DOI 10.1002/adfm.201304166

    View details for Web of Science ID 000338011200015

  • Controlling Solution-Phase Polymer Aggregation with Molecular Weight and Solvent Additives to Optimize Polymer-Fullerene Bulk Heterojunction Solar Cells ADVANCED ENERGY MATERIALS Bartelt, J. A., Douglas, J. D., Mateker, W. R., El Labban, A., Tassone, C. J., Toney, M. F., Frechet, J. M., Beaujuge, P. M., McGehee, M. D. 2014; 4 (9)

    View details for DOI 10.1002/aenm.201301733

    View details for Web of Science ID 000338022300012

  • How High Local Charge Carrier Mobility and an Energy Cascade in a Three-Phase Bulk Heterojunction Enable > 90% Quantum Efficiency ADVANCED MATERIALS Burke, T. M., McGehee, M. D. 2014; 26 (12): 1923-1928

    Abstract

    Charge generation in champion organic solar cells is highly efficient in spite of low bulk charge-carrier mobilities and short geminate-pair lifetimes. In this work, kinetic Monte Carlo simulations are used to understand efficient charge generation in terms of experimentally measured high local charge-carrier mobilities and energy cascades due to molecular mixing.

    View details for DOI 10.1002/adma.201304241

    View details for Web of Science ID 000333523600010

    View details for PubMedID 24375640

  • Efficient charge generation by relaxed charge-transfer states at organic interfaces NATURE MATERIALS Vandewal, K., Albrecht, S., Hoke, E. T., Graham, K. R., Widmer, J., Douglas, J. D., Schubert, M., Mateker, W. R., Bloking, J. T., Burkhard, G. F., Sellinger, A., Frechet, J. M., Amassian, A., Riede, M. K., McGehee, M. D., Neher, D., Salleo, A. 2014; 13 (1): 63-68

    Abstract

    Interfaces between organic electron-donating (D) and electron-accepting (A) materials have the ability to generate charge carriers on illumination. Efficient organic solar cells require a high yield for this process, combined with a minimum of energy losses. Here, we investigate the role of the lowest energy emissive interfacial charge-transfer state (CT1) in the charge generation process. We measure the quantum yield and the electric field dependence of charge generation on excitation of the charge-transfer (CT) state manifold via weakly allowed, low-energy optical transitions. For a wide range of photovoltaic devices based on polymer:fullerene, small-molecule:C60 and polymer:polymer blends, our study reveals that the internal quantum efficiency (IQE) is essentially independent of whether or not D, A or CT states with an energy higher than that of CT1 are excited. The best materials systems show an IQE higher than 90% without the need for excess electronic or vibrational energy.

    View details for DOI 10.1038/NMAT3807

    View details for Web of Science ID 000328942800020

  • Semi-Transparent Polymer Solar Cells with Excellent Sub-Bandgap Transmission for Third Generation Photovoltaics ADVANCED MATERIALS Beiley, Z. M., Christoforo, M. G., Gratia, P., Bowring, A. R., Eberspacher, P., Margulis, G. Y., Cabanetos, C., Beaujuge, P. M., Salleo, A., McGehee, M. D. 2013; 25 (48): 7020-7026

    Abstract

    Semi-transparent organic photovoltaics are of interest for a variety of photovoltaic applications, including solar windows and hybrid tandem photovoltaics. The figure shows a photograph of our semi-transparent solar cell, which has a power conversion efficiency of 5.0%, with an above bandgap transmission of 34% and a sub-bandgap transmission of 81%.

    View details for DOI 10.1002/adma.201301985

    View details for Web of Science ID 000328707300020

    View details for PubMedID 24123497

  • All-back-contact ultra-thin silicon nanocone solar cells with 13.7% power conversion efficiency NATURE COMMUNICATIONS Jeong, S., McGehee, M. D., Cui, Y. 2013; 4

    View details for DOI 10.1038/ncomms3950

    View details for Web of Science ID 000329397000003

  • Spray Deposition of Silver Nanowire Electrodes for Semitransparent Solid-State Dye-Sensitized Solar Cells ADVANCED ENERGY MATERIALS Margulis, G. Y., Christoforo, M. G., Lam, D., Beiley, Z. M., Bowring, A. R., Bailie, C. D., Salleo, A., McGehee, M. D. 2013; 3 (12): 1657-1663

    View details for DOI 10.1002/aenm.201300660

    View details for Web of Science ID 000328337500018

  • TiO2 Conduction Band Modulation with In2O3 Recombination Barrier Layers in Solid-State Dye-Sensitized Solar Cells JOURNAL OF PHYSICAL CHEMISTRY C Brennan, T. P., Tanskanen, J. T., Roelofs, K. E., To, J. W., Nguyen, W. H., Bakke, J. R., Ding, I., Hardin, B. E., Sellinger, A., McGehee, M. D., Bent, S. F. 2013; 117 (46): 24138-24149

    View details for DOI 10.1021/jp406789k

    View details for Web of Science ID 000327557300006

  • Dynamical Orientation of Large Molecules on Oxide Surfaces and its Implications for Dye-Sensitized Solar Cells CHEMISTRY OF MATERIALS Brennan, T. P., Tanskanen, J. T., Bakke, J. R., Nguyen, W. H., Nordlund, D., Toney, M. F., McGehee, M. D., Sellinger, A., Bent, S. F. 2013; 25 (21): 4354-4363

    View details for DOI 10.1021/cm402609k

    View details for Web of Science ID 000327045000026

  • Re-evaluating the Role of Sterics and Electronic Coupling in Determining the Open-Circuit Voltage of Organic Solar Cells ADVANCED MATERIALS Graham, K. R., Erwin, P., Nordlund, D., Vandewal, K., Li, R., Ndjawa, G. O., Hoke, E. T., Salleo, A., Thompson, M. E., McGehee, M. D., Amassian, A. 2013; 25 (42): 6076-6082

    View details for DOI 10.1002/adma.201301319

    View details for Web of Science ID 000327801900007

  • Improving the long-term stability of PBDTTPD polymer solar cells through material purification aimed at removing organic impurities ENERGY & ENVIRONMENTAL SCIENCE Mateker, W. R., Douglas, J. D., Cabanetos, C., Sachs-Quintana, I. T., Bartelt, J. A., Hoke, E. T., El Labban, A., Beaujuge, P. M., Frechet, J. M., McGehee, M. D. 2013; 6 (8): 2529-2537

    View details for DOI 10.1039/c3ee41328d

    View details for Web of Science ID 000321983800026

  • Highly soluble energy relay dyes for dye-sensitized solar cells. Physical chemistry chemical physics Margulis, G. Y., Lim, B., Hardin, B. E., Unger, E. L., Yum, J., Feckl, J. M., Fattakhova-Rohlfing, D., Bein, T., Grätzel, M., Sellinger, A., McGehee, M. D. 2013; 15 (27): 11306-11312

    Abstract

    High solubility is a requirement for energy relay dyes (ERDs) to absorb a large portion of incident light and significantly improve the efficiency of dye-sensitized solar cells (DSSCs). Two benzonitrile-soluble ERDs, BL302 and BL315, were synthesized, characterized, and resulted in a 65% increase in the efficiency of TT1-sensitized DSSCs. The high solubility (180 mM) of these ERDs allows for absorption of over 95% of incident light at their peak wavelength. The overall power conversion efficiency of DSSCs with BL302 and BL315 was found to be limited by their energy transfer efficiency of approximately 70%. Losses due to large pore size, dynamic collisional quenching of the ERD, energy transfer to desorbed sensitizing dyes and static quenching by complex formation were investigated and it was found that a majority of the losses are caused by the formation of statically quenched ERDs in solution.

    View details for DOI 10.1039/c3cp51018b

    View details for PubMedID 23733016

  • Parasitic Absorption and Internal Quantum Efficiency Measurements of Solid-State Dye Sensitized Solar Cells ADVANCED ENERGY MATERIALS Margulis, G. Y., Hardin, B. E., Ding, I., Hoke, E. T., McGehee, M. D. 2013; 3 (7): 959-966

    View details for DOI 10.1002/aenm.201300057

    View details for Web of Science ID 000327698200019

  • Molecular Intercalation and Cohesion of Organic Bulk Heterojunction Photovoltaic Devices ADVANCED FUNCTIONAL MATERIALS Bruner, C., Miller, N. C., McGehee, M. D., Dauskardt, R. H. 2013; 23 (22): 2863-2871

    View details for DOI 10.1002/adfm.201202969

    View details for Web of Science ID 000320006700010

  • The Importance of Fullerene Percolation in the Mixed Regions of Polymer-Fullerene Bulk Heterojunction Solar Cells ADVANCED ENERGY MATERIALS Bartelt, J. A., Beiley, Z. M., Hoke, E. T., Mateker, W. R., Douglas, J. D., Collins, B. A., Tumbleston, J. R., Graham, K. R., Amassian, A., Ade, H., Frechet, J. M., Toney, M. F., McGehee, M. D. 2013; 3 (3): 364-374

    View details for DOI 10.1002/aenm.201200637

    View details for Web of Science ID 000316117800015

  • Recombination in Polymer:Fullerene Solar Cells with Open-Circuit Voltages Approaching and Exceeding 1.0 V ADVANCED ENERGY MATERIALS Hoke, E. T., Vandewal, K., Bartelt, J. A., Mateker, W. R., Douglas, J. D., Noriega, R., Graham, K. R., Frechet, J. M., Salleo, A., McGehee, M. D. 2013; 3 (2): 220-230

    View details for DOI 10.1002/aenm.201200474

    View details for Web of Science ID 000314654500013

  • Fast-Track Solar Cells Nature McGehee, M., D. 2013; 501: 323
  • Spray Deposition of Silver Nanowire Electrodes for Semitransparent Solid-State Dye-Sensitized Solar Cells Advanced Energy Materials Margulis, G., Y., Christoforo, M., G., Lam, D., Beiley, Z., M., Bowring, A., R., Bailie, C., D., McGehee, M. D. 2013

    View details for DOI 10.1002/aenm.201300660

  • Semi-Transparent Polymer Solar Cells with Excellent Sub-Bandgap Transmission for Third Generation Photovoltaics Advanced Materials Beiley, Z., M., Christoforo, M., G., Gratia, P., Bowring, A., R., Eberspacher, P., Margulis, G., Y., McGehee, M. D. 2013

    View details for DOI 10.1002/adma.201301985

  • Parasitic Absorption and Internal Quantum Efficiency Measurements of Solid-State Dye Sensitized Solar Cells Advanced Energy Materials Margulis, G., Y., Hardin, B., E., Ding, I., K., Hoke, E., T., McGehee, M., D. 2013

    View details for DOI 10.1002/aenm.201300057

  • Use of X-Ray Diffraction, Molecular Simulations, and Spectroscopy to Determine the Molecular Packing in a Polymer-Fullerene Bimolecular Crystal ADVANCED MATERIALS Miller, N. C., Cho, E., Junk, M. J., Gysel, R., Risko, C., Kim, D., Sweetnam, S., Miller, C. E., Richter, L. J., Kline, R. J., Heeney, M., McCulloch, I., Amassian, A., Acevedo-Feliz, D., Knox, C., Hansen, M. R., Dudenko, D., Chmelka, B. F., Toney, M. F., Bredas, J., McGehee, M. D. 2012; 24 (45): 6071-?

    Abstract

    The molecular packing in a polymer: fullerene bimolecular crystal is determined using X-ray diffraction (XRD), molecular mechanics (MM) and molecular dynamics (MD) simulations, 2D solid-state NMR spectroscopy, and IR absorption spectroscopy. The conformation of the electron-donating polymer is significantly disrupted by the incorporation of the electron-accepting fullerene molecules, which introduce twists and bends along the polymer backbone and 1D electron-conducting fullerene channels.

    View details for DOI 10.1002/adma.201202293

    View details for Web of Science ID 000312130300013

    View details for PubMedID 22949357

  • Modeling low cost hybrid tandem photovoltaics with the potential for efficiencies exceeding 20% ENERGY & ENVIRONMENTAL SCIENCE Beiley, Z. M., McGehee, M. D. 2012; 5 (11): 9173-9179

    View details for DOI 10.1039/c2ee23073a

    View details for Web of Science ID 000310006200003

  • The Role of Electron Affinity in Determining Whether Fullerenes Catalyze or Inhibit Photooxidation of Polymers for Solar Cells ADVANCED ENERGY MATERIALS Hoke, E. T., Sachs-Quintana, I. T., Lloyd, M. T., Kauvar, I., Mateker, W. R., Nardes, A. M., Peters, C. H., Kopidakis, N., McGehee, M. D. 2012; 2 (11): 1351-1357

    View details for DOI 10.1002/aenm.201200169

    View details for Web of Science ID 000310678300009

  • Self-limited plasmonic welding of silver nanowire junctions NATURE MATERIALS Garnett, E. C., Cai, W., Cha, J. J., Mahmood, F., Connor, S. T., Christoforo, M. G., Cui, Y., McGehee, M. D., Brongersma, M. L. 2012; 11 (3): 241-249

    Abstract

    Nanoscience provides many strategies to construct high-performance materials and devices, including solar cells, thermoelectrics, sensors, transistors, and transparent electrodes. Bottom-up fabrication facilitates large-scale chemical synthesis without the need for patterning and etching processes that waste material and create surface defects. However, assembly and contacting procedures still require further development. Here, we demonstrate a light-induced plasmonic nanowelding technique to assemble metallic nanowires into large interconnected networks. The small gaps that form naturally at nanowire junctions enable effective light concentration and heating at the point where the wires need to be joined together. The extreme sensitivity of the heating efficiency on the junction geometry causes the welding process to self-limit when a physical connection between the wires is made. The localized nature of the heating prevents damage to low-thermal-budget substrates such as plastics and polymer solar cells. This work opens new avenues to control light, heat and mass transport at the nanoscale.

    View details for DOI 10.1038/NMAT3238

    View details for Web of Science ID 000300625500025

    View details for PubMedID 22306769

  • The renaissance of dye-sensitized solar cells NATURE PHOTONICS Hardin, B. E., Snaith, H. J., McGehee, M. D. 2012; 6 (3): 162-169

    View details for DOI 10.1038/NPHOTON.2012.22

    View details for Web of Science ID 000300935700011

  • The Mechanism of Burn-in Loss in a High Efficiency Polymer Solar Cell ADVANCED MATERIALS Peters, C. H., Sachs-Quintana, I. T., Mateker, W. R., Heumueller, T., Rivnay, J., Noriega, R., Beiley, Z. M., Hoke, E. T., Salleo, A., McGehee, M. D. 2012; 24 (5): 663-?

    Abstract

    Degradation in a high efficiency polymer solar cell is caused by the formation of states in the bandgap. These states increase the energetic disorder in the system. The power conversion efficiency loss does not occur when current is run through the device in the dark but occurs when the active layer is photo-excited.

    View details for DOI 10.1002/adma.201103010

    View details for Web of Science ID 000299466600009

    View details for PubMedID 21989825

  • Hole Transport Materials with Low Glass Transition Temperatures and High Solubility for Application in Solid-State Dye-Sensitized Solar Cells ACS NANO Leijtens, T., Ding, I., Giovenzana, T., Bloking, J. T., McGehee, M. D., Sellinger, A. 2012; 6 (2): 1455-1462

    Abstract

    We present the synthesis and device characterization of new hole transport materials (HTMs) for application in solid-state dye-sensitized solar cells (ssDSSCs). In addition to possessing electrical properties well suited for ssDSSCs, these new HTMs have low glass transition temperatures, low melting points, and high solubility, which make them promising candidates for increased pore filling into mesoporous titania films. Using standard device fabrication methods and Z907 as the sensitizing dye, power conversion efficiencies (PCE) of 2.94% in 2-?m-thick cells were achieved, rivaling the PCE obtained by control devices using the state-of-the-art HTM spiro-OMeTAD. In 6-?m-thick cells, the device performance is shown to be higher than that obtained using spiro-OMeTAD, making these new HTMs promising for preparing high-efficiency ssDSSCs.

    View details for DOI 10.1021/nn204296b

    View details for Web of Science ID 000300757900054

    View details for PubMedID 22230653

  • Hole Transport Materials for Application in Solid-State Dye-Sensitized Solar Sells (ssDSSC) with High Pore Filling ACS Nano Leijtens, T., Ding, I., K., Giovenzana, T., Bloking, J., T., McGehee, M., D., Sellinger, A. 2012; 6: 1455Ð1462
  • Renaissance of Dye-Sensitized Solar Cells Nature Photonics Hardin, B., E., Snaith, H., J., McGehee, M., D. 2012; 6: 162
  • Solution-Processed Organic Solar Cells with Power Conversion Efficiencies of 2.5% using Benzothiadiazole/Imide-Based Acceptors CHEMISTRY OF MATERIALS Bloking, J. T., Han, X., Higgs, A. T., Kastrop, J. P., Pandey, L., Norton, J. E., Risko, C., Chen, C. E., Bredas, J., McGehee, M. D., Sellinger, A. 2011; 23 (24): 5484-5490

    View details for DOI 10.1021/cm203111k

    View details for Web of Science ID 000298197300027

  • Paradigm Shifts in Dye-Sensitized Solar Cells SCIENCE McGehee, M. D. 2011; 334 (6056): 607-608

    View details for DOI 10.1126/science.1212818

    View details for Web of Science ID 000296494700035

  • Atomic Layer Deposition of CdS Quantum Dots for Solid-State Quantum Dot Sensitized Solar Cells ADVANCED ENERGY MATERIALS Brennan, T. P., Ardalan, P., Lee, H., Bakke, J. R., Ding, I., McGehee, M. D., Bent, S. F. 2011; 1 (6): 1169-1175

    View details for DOI 10.1002/aenm.201100363

    View details for Web of Science ID 000297056500031

  • 3,4-Disubstituted Polyalkylthiophenes for High-Performance Thin-Film Transistors and Photovoltaics JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Ko, S., Verploegen, E., Hong, S., Mondal, R., Hoke, E. T., Toney, M. F., McGehee, M. D., Bao, Z. 2011; 133 (42): 16722-16725

    Abstract

    We demonstrate that poly(3,4-dialkylterthiophenes) (P34ATs) have comparable transistor mobilities (0.17 cm(2) V(-1) s(-1)) and greater environmental stability (less degradation of on/off ratio) than regioregular poly(3-alkylthiophenes) (P3ATs). Unlike poly(3-hexylthiophene) (P3HT), P34ATs do not show a strong and distinct ?-? stacking in X-ray diffraction. This suggests that a strong ?-? stacking is not always necessary for high charge-carrier mobility and that other potential polymer packing motifs in addition to the edge-on structure (?-? stacking direction parallel to the substrate) can lead to a high carrier mobility. The high charge-carrier mobilities of the hexyl and octyl-substituted P34AT produce power conversion efficiencies of 4.2% in polymer:fullerene bulk heterojunction photovoltaic devices. An enhanced open-circuit voltage (0.716-0.771 eV) in P34AT solar cells relative to P3HT due to increased ionization potentials was observed.

    View details for DOI 10.1021/ja207429s

    View details for Web of Science ID 000296678200004

    View details for PubMedID 21970371

  • Morphology-Dependent Trap Formation in High Performance Polymer Bulk Heterojunction Solar Cells ADVANCED ENERGY MATERIALS Beiley, Z. M., Hoke, E. T., Noriega, R., Dacuna, J., Burkhard, G. F., Bartelt, J. A., Salleo, A., Toney, M. F., McGehee, M. D. 2011; 1 (5): 954-962

    View details for DOI 10.1002/aenm.201100204

    View details for Web of Science ID 000295140100034

  • Self-limited plasmonic nanowelding Garnett, E. C., Cha, J. J., Cai, W., Connor, S. T., Mahmood, F., Cui, Y., Brongersma, M. L., McGehee, M. D. AMER CHEMICAL SOC. 2011

    View details for Web of Science ID 000299378304386

  • Semiconductor contact effects in high-performance, air-stable, inverted organic solar cells Garnett, E. C., Brongersma, M. L., Cui, Y., McGehee, M. D. AMER CHEMICAL SOC. 2011

    View details for Web of Science ID 000299378303685

  • Photovoltaic polymeric materials McGehee, M. D., Beiley, Z. M., Peters, C. H., Sachs-Quintana, I. T., Hoke, E. T., Kastrop, J. P., Burkhard, G. F. AMER CHEMICAL SOC. 2011

    View details for Web of Science ID 000299378307024

  • Energy and Hole Transfer between Dyes Attached to Titania in Cosensitized Dye-Sensitized Solar Cells JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Hardin, B. E., Sellinger, A., Moehl, T., Humphry-Baker, R., Moser, J., Wang, P., Zakeeruddin, S. M., Graetzel, M., McGehee, M. D. 2011; 133 (27): 10662-10667

    Abstract

    Cosensitization of broadly absorbing ruthenium metal complex dyes with highly absorptive near-infrared (NIR) organic dyes is a clear pathway to increase near-infrared light harvesting in liquid-based dye-sensitized solar cells (DSCs). In cosensitized DSCs, dyes are intimately mixed, and intermolecular charge and energy transfer processes play an important role in device performance. Here, we demonstrate that an organic NIR dye incapable of hole regeneration is able to produce photocurrent via intermolecular energy transfer with an average excitation transfer efficiency of over 25% when cosensitized with a metal complex sensitizing dye (SD). We also show that intermolecular hole transfer from the SD to NIR dye is a competitive process with dye regeneration, reducing the internal quantum efficiency and the electron lifetime of the DSC. This work demonstrates the general feasibility of using energy transfer to boost light harvesting from 700 to 800 nm and also highlights a key challenge for developing highly efficient cosensitized dye-sensitized solar cells.

    View details for DOI 10.1021/ja2042172

    View details for Web of Science ID 000293149800051

    View details for PubMedID 21619039

  • Smooth Nanowire/Polymer Composite Transparent Electrodes ADVANCED MATERIALS Gaynor, W., Burkhard, G. F., McGehee, M. D., Peumans, P. 2011; 23 (26): 2905-?

    View details for DOI 10.1002/adma.201100566

    View details for Web of Science ID 000293661100002

    View details for PubMedID 21538594

  • High Efficiency Polymer Solar Cells with Long Operating Lifetimes ADVANCED ENERGY MATERIALS Peters, C. H., Sachs-Quintana, I. T., Kastrop, J. P., Beaupre, S., Leclerc, M., McGehee, M. D. 2011; 1 (4): 491-494

    View details for DOI 10.1002/aenm.201100138

    View details for Web of Science ID 000293795800004

  • Laminating solution-processed silver nanowire mesh electrodes onto solid-state dye-sensitized solar cells ORGANIC ELECTRONICS Hardin, B. E., Gaynor, W., Ding, I., Rim, S., Peumans, P., McGehee, M. D. 2011; 12 (6): 875-879

    View details for DOI 10.1016/j.orgel.2011.03.006

    View details for Web of Science ID 000290024900001

  • Influence of the hole-transport layer on the initial behavior and lifetime of inverted organic photovoltaics SOLAR ENERGY MATERIALS AND SOLAR CELLS Lloyd, M. T., Peters, C. H., Garcia, A., Kauvar, I. V., Berry, J. J., Reese, M. O., McGehee, M. D., Ginley, D. S., Olson, D. C. 2011; 95 (5): 1382-1388

    View details for DOI 10.1016/j.solmat.2010.12.036

    View details for Web of Science ID 000290359200019

  • The Effect of Hole Transport Material Pore Filling on Photovoltaic Performance in Solid-State Dye-Sensitized Solar Cells ADVANCED ENERGY MATERIALS Melas-Kyriazi, J., Ding, I., Marchioro, A., Punzi, A., Hardin, B. E., Burkhard, G. F., Tetreault, N., Graetzel, M., Moser, J., McGehee, M. D. 2011; 1 (3): 407-414

    View details for DOI 10.1002/aenm.201100046

    View details for Web of Science ID 000291728400016

  • The Phase Behavior of a Polymer-Fullerene Bulk Heterojunction System that Contains Bimolecular Crystals JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS Miller, N. C., Gysel, R., Miller, C. E., Verploegen, E., Beiley, Z., Heeney, M., McCulloch, I., Bao, Z., Toney, M. F., McGehee, M. D. 2011; 49 (7): 499-503

    View details for DOI 10.1002/polb.22214

    View details for Web of Science ID 000288541400003

  • Recent progress with organic and dye-sensitized solar cells McGehee, M. D. AMER CHEMICAL SOC. 2011

    View details for Web of Science ID 000291982804353

  • Incorporating Multiple Energy Relay Dyes in Liquid Dye-Sensitized Solar Cells CHEMPHYSCHEM Yum, J., Hardin, B. E., Hoke, E. T., Baranoff, E., Zakeeruddin, S. M., Nazeeruddin, M. K., Torres, T., McGehee, M. D., Graetzel, M. 2011; 12 (3): 657-661

    Abstract

    Panchromatic response is essential to increase the light-harvesting efficiency in solar conversion systems. Herein we show increased light harvesting from using multiple energy relay dyes inside dye-sensitized solar cells. Additional photoresponse from 400-590 nm matching the optical window of the zinc phthalocyanine sensitizer was observed due to Förster resonance energy transfer (FRET) from the two energy relay dyes to the sensitizing dye. The complementary absorption spectra of the energy relay dyes and high excitation transfer efficiencies result in a 35% increase in photovoltaic performance.

    View details for DOI 10.1002/cphc.201000854

    View details for Web of Science ID 000288086800023

    View details for PubMedID 21344598

  • Effects of Nanostructured Back Reflectors on the External Quantum Efficiency in Thin Film Solar Cells NANO RESEARCH Hsu, C., Burkhard, G. F., McGehee, M. D., Cui, Y. 2011; 4 (2): 153-158

    View details for DOI 10.1007/s12274-010-0064-y

    View details for Web of Science ID 000287974000001

  • Effects of Self-Assembled Monolayers on Solid-State CdS Quantum Dot Sensitized Solar Cells ACS NANO Ardalan, P., Brennan, T. P., Lee, H., Bakke, J. R., Ding, I., McGehee, M. D., Bent, S. F. 2011; 5 (2): 1495-1504

    Abstract

    Quantum dot sensitized solar cells (QDSSCs) are of interest for solar energy conversion because of their tunable band gap and promise of stable, low-cost performance. We have investigated the effects of self-assembled monolayers (SAMs) with phosphonic acid headgroups on the bonding and performance of cadmium sulfide (CdS) solid-state QDSSCs. CdS quantum dots ?2 to ?6 nm in diameter were grown on SAM-passivated planar or nanostructured TiO(2) surfaces by successive ionic layer adsorption and reaction (SILAR), and photovoltaic devices were fabricated with spiro-OMeTAD as the solid-state hole conductor. X-ray photoelectron spectroscopy, Auger electron spectroscopy, ultraviolet-visible spectroscopy, scanning electron microscopy, transmission electron microscopy, water contact angle measurements, ellipsometry, and electrical measurements were employed to characterize the materials and the resulting device performance. The data indicate that the nature of the SAM tailgroup does not significantly affect the uptake of CdS quantum dots on TiO(2) nor their optical properties, but the presence of the SAM does have a significant effect on the photovoltaic device performance. Interestingly, we observe up to ?3 times higher power conversion efficiencies in devices with a SAM compared to those without the SAM.

    View details for DOI 10.1021/nn103371v

    View details for Web of Science ID 000287553800093

    View details for PubMedID 21299223

  • Plasmonic Dye-Sensitized Solar Cells ADVANCED ENERGY MATERIALS Ding, I., Zhu, J., Cai, W., Moon, S., Cai, N., Wang, P., Zakeeruddin, S. M., Graetzel, M., Brongersma, M. L., Cui, Y., McGehee, M. D. 2011; 1 (1): 52-57

    View details for DOI 10.1002/aenm.201000041

    View details for Web of Science ID 000291725000004

  • Nanowire Solar Cells ANNUAL REVIEW OF MATERIALS RESEARCH, VOL 41 Garnett, E. C., Brongersma, M. L., Cui, Y., McGehee, M. D. 2011; 41: 269-295

    View details for DOI 10.1146/annurev-matsci-062910-100434

    View details for Web of Science ID 000294028600011

  • Nanowire Solar Cells Annual Review of Materials Research Garnett, E., C., Brongersma, M., L., Cui, Y., McGehee, M., D. 2011; 41: 269
  • A quantum-chemical perspective into low optical-gap polymers for highly-efficient organic solar cells CHEMICAL SCIENCE Risko, C., McGehee, M. D., Bredas, J. 2011; 2 (7): 1200-1218

    View details for DOI 10.1039/c0sc00642d

    View details for Web of Science ID 000291610600001

  • Transparent electrode requirements for thin film solar cell modules ENERGY & ENVIRONMENTAL SCIENCE Rowell, M. W., McGehee, M. D. 2011; 4 (1): 131-134

    View details for DOI 10.1039/c0ee00373e

    View details for Web of Science ID 000285748400010

  • Electrospun Metal Nanofiber Webs as High-Performance Transparent Electrode NANO LETTERS Wu, H., Hu, L., Rowell, M. W., Kong, D., Cha, J. J., McDonough, J. R., Zhu, J., Yang, Y., McGehee, M. D., Cui, Y. 2010; 10 (10): 4242-4248

    Abstract

    Transparent electrodes, indespensible in displays and solar cells, are currently dominated by indium tin oxide (ITO) films although the high price of indium, brittleness of films, and high vacuum deposition are limiting their applications. Recently, solution-processed networks of nanostructures such as carbon nanotubes (CNTs), graphene, and silver nanowires have attracted great attention as replacements. A low junction resistance between nanostructures is important for decreasing the sheet resistance. However, the junction resistances between CNTs and boundry resistances between graphene nanostructures are too high. The aspect ratios of silver nanowires are limited to ?100, and silver is relatively expensive. Here, we show high-performance transparent electrodes with copper nanofiber networks by a low-cost and scalable electrospinning process. Copper nanofibers have ultrahigh aspect ratios of up to 100000 and fused crossing points with ultralow junction resistances, which result in high transmitance at low sheet resistance, e.g., 90% at 50 ?/sq. The copper nanofiber networks also show great flexibility and stretchabilty. Organic solar cells using copper nanowire networks as transparent electrodes have a power efficiency of 3.0%, comparable to devices made with ITO electrodes.

    View details for DOI 10.1021/nl102725k

    View details for Web of Science ID 000282727600074

    View details for PubMedID 20738115

  • Indacenodithiophene Semiconducting Polymers for High-Performance, Air-Stable Transistors JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Zhang, W., Smith, J., Watkins, S. E., Gysel, R., McGehee, M., Salleo, A., Kirkpatrick, J., Ashraf, S., Anthopoulos, T., Heeney, M., McCulloch, I. 2010; 132 (33): 11437-11439

    Abstract

    High-performance, solution-processed transistors fabricated from semiconducting polymers containing indacenodithiohene repeat units are described. The bridging functions on the backbone contribute to suppressing large-scale crystallization in thin films. However, charge carrier mobilities of up to 1 cm(2)/(V s) for a benzothiadiazole copolymer were reported and, coupled with both ambient stability and long-wavelength absorption, make this family of polymers particularly attractive for application in next-generation organic optoelectronics.

    View details for DOI 10.1021/ja1049324

    View details for Web of Science ID 000281066400019

    View details for PubMedID 20677750

  • Tuning the Optoelectronic Properties of Vinylene-Linked Donor-Acceptor Copolymers for Organic Photovoltaics MACROMOLECULES Ko, S., Mondal, R., Risko, C., Lee, J. K., Hong, S., McGehee, M. D., Bredas, J., Bao, Z. 2010; 43 (16): 6685-6698

    View details for DOI 10.1021/ma101088f

    View details for Web of Science ID 000280855000023

  • Improving efficiency of dye-sensitized solar cells (DSCs) with energy relay dyes and light trapping McGehee, M. D., Graetzel, M., Hardin, B. E., Ding, I. AMER CHEMICAL SOC. 2010

    View details for Web of Science ID 000208164706367

  • Improving bulk heterojunction solar cells through controlling their nanostructure Cates, N. C., Burkhard, G. F., Gysel, R., Beiley, Z., Hoke, E. T., Scully, S. R., Miller, C. E., Toney, M. F., Heeney, M., McCulloch, I., McGehee, M. D. AMER CHEMICAL SOC. 2010

    View details for Web of Science ID 000208164702862

  • Anthradithiophene-Containing Copolymers for Thin-Film Transistors and Photovoltaic Cells MACROMOLECULES Jiang, Y., Okamoto, T., Becerril, H. A., Hong, S., Tang, M. L., Mayer, A. C., Parmer, J. E., McGehee, M. D., Bao, Z. 2010; 43 (15): 6361-6367

    View details for DOI 10.1021/ma1001639

    View details for Web of Science ID 000280743300017

  • Accounting for Interference, Scattering, and Electrode Absorption to Make Accurate Internal Quantum Efficiency Measurements in Organic and Other Thin Solar Cells ADVANCED MATERIALS Burkhard, G. F., Hoke, E. T., McGehee, M. D. 2010; 22 (30): 3293-?

    View details for DOI 10.1002/adma.201000883

    View details for Web of Science ID 000281328500012

    View details for PubMedID 20517871

  • High Excitation Transfer Efficiency from Energy Relay Dyes in Dye-Sensitized Solar Cells NANO LETTERS Hardin, B. E., Yum, J., Hoke, E. T., Jun, Y. C., Pechy, P., Torres, T., Brongersma, M. L., Nazeeruddin, M. K., Graetzel, M., McGehee, M. D. 2010; 10 (8): 3077-3083

    Abstract

    The energy relay dye, 4-(Dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM), was used with a near-infrared sensitizing dye, TT1, to increase the overall power conversion efficiency of a dye-sensitized solar cell (DSC) from 3.5% to 4.5%. The unattached DCM dyes exhibit an average excitation transfer efficiency (ETE) of 96% inside TT1-covered, mesostructured TiO(2) films. Further performance increases were limited by the solubility of DCM in an acetonitrile based electrolyte. This demonstration shows that energy relay dyes can be efficiently implemented in optimized dye-sensitized solar cells, but also highlights the need to design highly soluble energy relay dyes with high molar extinction coefficients.

    View details for DOI 10.1021/nl1016688

    View details for Web of Science ID 000280728900058

    View details for PubMedID 20617816

  • Response to "Comment on 'Energy transfer in nanowire solar cells with photon-harvesting shells'" [J. Appl. Phys. 105, 124509 (2009)] JOURNAL OF APPLIED PHYSICS Peters, C. H., Guichard, A. R., Hryciw, A. C., Brongersma, M. L., McGehee, M. D. 2010; 108 (2)

    View details for DOI 10.1063/1.3452392

    View details for Web of Science ID 000280909900118

  • Deposition of hole-transport materials in solid-state dye-sensitized solar cells by doctor-blading ORGANIC ELECTRONICS Ding, I., Melas-Kyriazi, J., Cevey-Ha, N., Chittibabu, K. G., Zakeeruddin, S. M., Graetzel, M., McGehee, M. D. 2010; 11 (7): 1217-1222

    View details for DOI 10.1016/j.orgel.2010.04.019

    View details for Web of Science ID 000278530500011

  • Effects of Intercalation on the Hole Mobility of Amorphous Semiconducting Polymer Blends CHEMISTRY OF MATERIALS Cates, N. C., Gysel, R., Dahl, J. E., Sellinger, A., McGehee, M. D. 2010; 22 (11): 3543-3548

    View details for DOI 10.1021/cm1008619

    View details for Web of Science ID 000278149300031

  • Improving light absorption in thin silicon nanowire photovoltaics Garnett, E. C., Peters, C., Brongersma, M., Cui, Y., McGehee, M. AMER CHEMICAL SOC. 2010

    View details for Web of Science ID 000208189302589

  • Effect of absorption coefficient on the performance of organic photovoltaics based on vinylene linked copolymers Ko, S., Mondal, R., Risko, C. M., Lee, J. K., Hong, S., McGehee, M. D., Bredas, J. L., Bao, Z. AMER CHEMICAL SOC. 2010

    View details for Web of Science ID 000208189304616

  • Electric force microscopy of bundles and bundle junctions in carbon nanotube network transparent conductors Rowell, M. W., Topinka, M. A., Hellstrom, S., Bao, Z., Goldhaber-Gordon, D., McGehee, M. D. AMER CHEMICAL SOC. 2010

    View details for Web of Science ID 000208189303078

  • Effects of bulk heterojunction nanostructure on solar cell performance Burkhard, G. F., Cates, N. C., Gysel, R., Beiley, Z., Hoke, E. T., Scully, S. R., Miller, C. E., Toney, M. F., Heeney, M., McCullough, I., McGehee, M. D. AMER CHEMICAL SOC. 2010

    View details for Web of Science ID 000208189304560

  • Modeling the efficiency of Forster resonant energy transfer from energy relay dyes in dye-sensitized solar cells OPTICS EXPRESS Hoke, E. T., Hardin, B. E., McGehee, M. D. 2010; 18 (4): 3893-3904

    Abstract

    Förster resonant energy transfer can improve the spectral breadth, absorption and energy conversion efficiency of dye sensitized solar cells. In this design, unattached relay dyes absorb the high energy photons and transfer the excitation to sensitizing dye molecules by Förster resonant energy transfer. We use an analytic theory to calculate the excitation transfer efficiency from the relay dye to the sensitizing dye accounting for dynamic quenching and relay dye diffusion. We present calculations for pores of cylindrical and spherical geometry and examine the effects of the Förster radius, the pore size, sensitizing dye surface concentration, collisional quenching rate, and relay dye lifetime. We find that the excitation transfer efficiency can easily exceed 90% for appropriately chosen dyes and propose two different strategies for selecting dyes to achieve record power conversion efficiencies.

    View details for Web of Science ID 000274795700072

    View details for PubMedID 20389400

  • Phosphorescent energy relay dye for improved light harvesting response in liquid dye-sensitized solar cells ENERGY & ENVIRONMENTAL SCIENCE Yum, J., Baranoff, E., Hardin, B. E., Hoke, E. T., McGehee, M. D., Nueesch, F., Graetzel, M., Nazeeruddin, M. K. 2010; 3 (4): 434-437

    View details for DOI 10.1039/b925473k

    View details for Web of Science ID 000276378000006

  • FACETING AND DISORDER IN NANOWIRE SOLAR CELL ARRAYS Pickett, E., Gu, A., Huo, Y., Garnett, E., Hu, S., Sarmiento, T., Thombare, S., Liang, D., Li, S., Cui, Y., McGehee, M., McIntyre, P., Harris, J. IEEE. 2010: 1848-1853

    View details for Web of Science ID 000287579502020

  • Modeling the Efficiency of Förster Resonant Energy Transfer from Energy Relay Dyes in Dye-Sensitized Solar Cells Optics Express Hoke, E., T., Hardin, B., E., McGehee, M., D. 2010; 18: 3893
  • Confinement Effects of P3HT in Nanochannels and Their Implications for Bulk Heterojunction Solar Cells JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY Kim, M., Suh, M., Gowrishankar, V., McGehee, M. D., Kwon, Y. 2010; 10 (1): 279-284

    Abstract

    We studied the properties of regioregular P3HT conducting polymers with three different molecular weights infiltrated into the pores of mesoporous titania thin films. The titania thin films, prepared by self-organization of titania species with a non-ionic triblock copolymer F127 followed by calcination to remove organics, have arrays of 7 nm vertical nanochannels. The UV-Vis spectra of the P3HT-titania nanocomposite films revealed that the interstrand interactions between P3HT chains were weakened by the infiltration. Such an effect increases as the molecular weight of P3HT increases and as the infiltration temperature increases. Consequently, the efficiency of the solar cells, assembled by using the P3HT infiltrated mesoporous titania thin films, was the highest with the smallest P3HT, contrary to the generally accepted practice of using high molecular weight P3HT for forming bulk heterojunction solar cells.

    View details for DOI 10.1166/jnn.2010.1489

    View details for Web of Science ID 000272388700042

    View details for PubMedID 20352847

  • Thiophene-rich fused-aromatic thienopyrazine acceptor for donor-acceptor low band-gap polymers for OTFT and polymer solar cell applications JOURNAL OF MATERIALS CHEMISTRY Mondal, R., Becerril, H. A., Verploegen, E., Kim, D., Norton, J. E., Ko, S., Miyaki, N., Lee, S., Toney, M. F., Bredas, J., McGehee, M. D., Bao, Z. 2010; 20 (28): 5823-5834

    View details for DOI 10.1039/c0jm00903b

    View details for Web of Science ID 000279565900008

  • Tuning the Properties of Polymer Bulk Heterojunction Solar Cells by Adjusting Fullerene Size to Control Intercalation NANO LETTERS Cates, N. C., Gysel, R., Beiley, Z., Miller, C. E., Toney, M. F., Heeney, M., McCulloch, I., McGehee, M. D. 2009; 9 (12): 4153-4157

    Abstract

    We demonstrate that intercalation of fullerene derivatives between the side chains of conjugated polymers can be controlled by adjusting the fullerene size and compare the properties of intercalated and nonintercalated poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene (pBTTT):fullerene blends. The intercalated blends, which exhibit optimal solar-cell performance at 1:4 polymer:fullerene by weight, have better photoluminescence quenching and lower absorption than the nonintercalated blends, which optimize at 1:1. Understanding how intercalation affects performance will enable more effective design of polymer:fullerene solar cells.

    View details for DOI 10.1021/nl9023808

    View details for Web of Science ID 000272395400034

    View details for PubMedID 19780570

  • Incomplete Exciton Harvesting from Fullerenes in Bulk Heterojunction Solar Cells NANO LETTERS Burkhard, G. F., Hoke, E. T., Scully, S. R., McGehee, M. D. 2009; 9 (12): 4037-4041

    Abstract

    We investigate the internal quantum efficiencies (IQEs) of high efficiency poly-3-hexylthiophene:[6,6]-phenyl-C(61)-butyric acid methyl ester (P3HT:PCBM) solar cells and find them to be lower at wavelengths where the PCBM absorbs. Because the exciton diffusion length in PCBM is too small, excitons generated in PCBM decay before reaching the donor-acceptor interface. This result has implications for most state of the art organic solar cells, since all of the most efficient devices use fullerenes as electron acceptors.

    View details for DOI 10.1021/nl902205n

    View details for Web of Science ID 000272395400014

    View details for PubMedID 19810728

  • Intercalation in polymer-molecule blends Cates, N. C., Gysel, R., Beiley, Z., Miller, C. E., Toney, M. F., Heeney, M., McCulloch, I., McGehee, M. D. AMER CHEMICAL SOC. 2009

    View details for Web of Science ID 000207861905497

  • New anthradithiophene-containing copolymers for thin-film transistor and solar cells Jiang, Y., Okamoto, T., Becerril, H. A., Tang, M. L., Mayer, A. C., Parmer, J. D., McGehee, M. D., Bao, Z. AMER CHEMICAL SOC. 2009

    View details for Web of Science ID 000207861905723

  • Controlling band gap by rigid unit modification of thienopyrazine based copolymers Mondol, R., Becerril, H. A., Miyaki, N., Parmer, J. D., McGehee, M. D., Bao, Z. AMER CHEMICAL SOC. 2009

    View details for Web of Science ID 000207861905806

  • Synthesis of Acenaphthyl and Phenanthrene Based Fused-Aromatic Thienopyrazine Co-Polymers for Photovoltaic and Thin Film Transistor Applications CHEMISTRY OF MATERIALS Mondal, R., Miyaki, N., Becerril, H. A., Norton, J. E., Parmer, J., Mayer, A. C., Tang, M. L., Bredas, J., McGehee, M. D., Bao, Z. 2009; 21 (15): 3618-3628

    View details for DOI 10.1021/cm900788e

    View details for Web of Science ID 000268523300021

  • Pore-Filling of Spiro-OMeTAD in Solid-State Dye Sensitized Solar Cells: Quantification, Mechanism, and Consequences for Device Performance ADVANCED FUNCTIONAL MATERIALS Ding, I., Tetreault, N., Brillet, J., Hardin, B. E., Smith, E. H., Rosenthal, S. J., Sauvage, F., Graetzel, M., McGehee, M. D. 2009; 19 (15): 2431-2436

    View details for DOI 10.1002/adfm.200900541

    View details for Web of Science ID 000269021500010

  • Increased light harvesting in dye-sensitized solar cells with energy relay dyes NATURE PHOTONICS Hardin, B. E., Hoke, E. T., Armstrong, P. B., Yum, J., Comte, P., Torres, T., Frechet, J. M., Nazeeruddin, M. K., Graetzel, M., McGehee, M. D. 2009; 3 (7): 406-411

    View details for DOI 10.1038/NPHOTON.2009.96

    View details for Web of Science ID 000268067700017

  • Energy transfer in nanowire solar cells with photon-harvesting shells Peters, C. H., Guichard, A. R., Hryciw, A. C., Brongersma, M. L., McGehee, M. D. AMER INST PHYSICS. 2009

    View details for DOI 10.1063/1.3153281

    View details for Web of Science ID 000267599600137

  • Charge Transport in Interpenetrating Networks of Semiconducting and Metallic Carbon Nanotubes NANO LETTERS Topinka, M. A., Rowell, M. W., Goldhaber-Gordon, D., McGehee, M. D., Hecht, D. S., Gruner, G. 2009; 9 (5): 1866-1871

    Abstract

    Carbon nanotube network field effect transistors (CNTN-FETs) are promising candidates for low cost macroelectronics. We investigate the microscopic transport in these devices using electric force microscopy and simulations. We find that in many CNTN-FETs the voltage drops abruptly at a point in the channel where the current is constricted to just one tube. We also model the effect of varying the semiconducting/metallic tube ratio. The effect of Schottky barriers on both conductance within semiconducting tubes and conductance between semiconducting and metallic tubes results in three possible types of CNTN-FETs with fundamentally different gating mechanisms. We describe this with an electronic phase diagram.

    View details for DOI 10.1021/nl803849e

    View details for Web of Science ID 000266157100025

    View details for PubMedID 19331424

  • Overcoming recombination NATURE PHOTONICS McGehee, M. D. 2009; 3 (5): 250-252

    View details for DOI 10.1038/nphoton.2009.54

    View details for Web of Science ID 000266218600007

  • Bimolecular Crystals of Fullerenes in Conjugated Polymers and the Implications of Molecular Mixing for Solar Cells ADVANCED FUNCTIONAL MATERIALS Mayer, A. C., Toney, M. F., Scully, S. R., Rivnay, J., Brabec, C. J., Scharber, M., Koppe, M., Heeney, M., McCulloch, I., McGehee, M. D. 2009; 19 (8): 1173-1179

    View details for DOI 10.1002/adfm.200801684

    View details for Web of Science ID 000265855700004

  • PHYS 240-Bimolecular crystals and intercalated molecular structures of polymer/fullerene in bulk heterojunction solar cells McGehee, M. D., Mayer, A. C., Toney, M. F., Scully, S. R., Rivnay, J., Cates, N. C., Gysel, R., Heeney, M., McCulloch, I. AMER CHEMICAL SOC. 2009

    View details for Web of Science ID 000207857808057

  • Improving efficiency of solid-state dye sensitized solar cells (DSCs) through increased pore filling and Forster energy transfer McGehee, M. D., Graetzel, M., Ding, I., Hardin, B. E. AMER CHEMICAL SOC. 2009

    View details for Web of Science ID 000207857807193

  • New fused-ring polymers with low-bandgap and good charge mobility for solar cells Becerril, H. A., Jiang, Y., Miyaki, N., Okamoto, T., Mondal, R., Hong, S., Ko, S., Lee, S., Parmer, J., Mayer, A. C., McGehee, M. D., Bao, Z. AMER CHEMICAL SOC. 2009

    View details for Web of Science ID 000207857807713

  • Low band-gap polymers based on fused aromatic thienopyrazine for photovoltaic applications Ko, S., Miyaki, N., Mondal, R., Becerril, H. A., Parmer, J., Myer, A. C., McGehee, M. D., Bao, Z. AMER CHEMICAL SOC. 2009

    View details for Web of Science ID 000207857807503

  • Nanostructured Organic-Inorganic Hybrid Solar Cells MRS BULLETIN McGehee, M. D. 2009; 34 (2): 95-100

    View details for Web of Science ID 000263799400015

  • Panchromatic Response in Solid-State Dye-Sensitized Solar Cells Containing Phosphorescent Energy Relay Dyes ANGEWANDTE CHEMIE-INTERNATIONAL EDITION Yum, J., Hardin, B. E., Moon, S., Baranoff, E., Nuesch, F., McGehee, M. D., Gratzel, M., Nazeeruddin, M. K. 2009; 48 (49): 9277-9280

    View details for DOI 10.1002/anie.200904725

    View details for Web of Science ID 000272500900013

    View details for PubMedID 19899176

  • Nanostructured Organic–Inorganic Hybrid Solar Cells Materials Research Society Bulletin McGehee, M., D. 2009; 34: 95
  • Transistor and solar cell performance of donor-acceptor low bandgap copolymers bearing an acenaphtho[1,2-b]thieno[3,4-e]pyrazine (ACTP) motif JOURNAL OF MATERIALS CHEMISTRY Becerril, H. A., Miyaki, N., Tang, M. L., Mondal, R., Sun, Y., Mayer, A. C., Parmer, J. E., McGehee, M. D., Bao, Z. 2009; 19 (5): 591-593

    View details for DOI 10.1039/b819210c

    View details for Web of Science ID 000262547000003

  • Optical Absorption Enhancement in Amorphous Silicon Nanowire and Nanocone Arrays NANO LETTERS Zhu, J., Yu, Z., Burkhard, G. F., Hsu, C., Connor, S. T., Xu, Y., Wang, Q., McGehee, M., Fan, S., Cui, Y. 2009; 9 (1): 279-282

    Abstract

    Hydrogenated amorphous Si (a-Si:H) is an important solar cell material. Here we demonstrate the fabrication of a-Si:H nanowires (NWs) and nanocones (NCs), using an easily scalable and IC-compatible process. We also investigate the optical properties of these nanostructures. These a-Si:H nanostructures display greatly enhanced absorption over a large range of wavelengths and angles of incidence, due to suppressed reflection. The enhancement effect is particularly strong for a-Si:H NC arrays, which provide nearly perfect impedance matching between a-Si:H and air through a gradual reduction of the effective refractive index. More than 90% of light is absorbed at angles of incidence up to 60 degrees for a-Si:H NC arrays, which is significantly better than NW arrays (70%) and thin films (45%). In addition, the absorption of NC arrays is 88% at the band gap edge of a-Si:H, which is much higher than NW arrays (70%) and thin films (53%). Our experimental data agree very well with simulation. The a-Si:H nanocones function as both absorber and antireflection layers, which offer a promising approach to enhance the solar cell energy conversion efficiency.

    View details for DOI 10.1021/nl802886y

    View details for Web of Science ID 000262519100052

    View details for PubMedID 19072061

  • Molecular design for improved photovoltaic efficiency: band gap and absorption coefficient engineering JOURNAL OF MATERIALS CHEMISTRY Mondal, R., Ko, S., Norton, J. E., Miyaki, N., Becerril, H. A., Verploegen, E., Toney, M. F., Bredas, J., McGehee, M. D., Bao, Z. 2009; 19 (39): 7195-7197

    View details for DOI 10.1039/b915222a

    View details for Web of Science ID 000270382400004

  • Synthesis and characterization of pentacene- and anthradithiophene-fluorene conjugated copolymers synthesized by Suzuki reactions MACROMOLECULES Okamoto, T., Jiang, Y., Qu, F., Mayer, A. C., Parmer, J. E., McGehee, M. D., Bao, Z. 2008; 41 (19): 6977-6980

    View details for DOI 10.1021/ma800931a

    View details for Web of Science ID 000259859800020

  • Nanostructured Titania-Polymer Photovoltaic Devices Made Using PFPE-Based Nanomolding Techniques CHEMISTRY OF MATERIALS Williams, S. S., Hampton, M. J., Gowrishankar, V., Ding, I., Templeton, J. L., Samulski, E. T., DeSimone, J. M., McGehee, M. D. 2008; 20 (16): 5229-5234

    View details for DOI 10.1021/cm800729q

    View details for Web of Science ID 000258580500019

  • PMSE 453-Transparent electrodes based on conducting polymers and carbon nanotubes McGehee, M. D. AMER CHEMICAL SOC. 2008

    View details for Web of Science ID 000270280001423

  • PMSE 156-Novel acenaphthylthienopyrazine based low band-gap polymers for solar cell applications Miyaki, N., Mondal, R., Parmer, J., Myer, A. C., McGehee, M. D., Bao, Z. AMER CHEMICAL SOC. 2008

    View details for Web of Science ID 000270280001210

  • COLL 91-The importance of P3HT crystallite orientation for charge transport in solar cells McGehee, M. D., Mayer, A. C., Hardin, B. E., Toney, M. F. AMER CHEMICAL SOC. 2008

    View details for Web of Science ID 000271775103522

  • Organic bulk heterojunction solar cells using poly(2,5-bis(3-tetradecyllthiophen-2-yl)thieno[3,2,-b]thiophene) APPLIED PHYSICS LETTERS Parmer, J. E., Mayer, A. C., Hardin, B. E., Scully, S. R., McGehee, M. D., Heeney, M., McCulloch, I. 2008; 92 (11)

    View details for DOI 10.1063/1.2899996

    View details for Web of Science ID 000254292400100

  • Exciton harvesting, charge transfer, and charge-carrier transport in amorphous-silicon nanopillar/polymer hybrid solar cells JOURNAL OF APPLIED PHYSICS Gowrishankar, V., Scully, S. R., Chan, A. T., McGehee, M. D., Wang, Q., Branz, H. M. 2008; 103 (6)

    View details for DOI 10.1063/1.2896583

    View details for Web of Science ID 000254536900127

  • Organic Semiconductors for Low-Cost Solar Cells PHYSICS OF SUSTAINABLE ENERGY McGehee, M. D., Goh, C. 2008; 1044: 322-330

    View details for Web of Science ID 000259999800023

  • An effective light trapping configuration for thin-film solar cells APPLIED PHYSICS LETTERS Rim, S., Zhao, S., Scully, S. R., McGehee, M. D., Peumans, P. 2007; 91 (24)

    View details for DOI 10.1063/1.2789677

    View details for Web of Science ID 000251678700073

  • Polymer-based solar cells MATERIALS TODAY Mayer, A. C., Scully, S. R., Hardin, B. E., Rowell, M. W., McGehee, M. D. 2007; 10 (11): 28-33

    View details for Web of Science ID 000250776600016

  • Long-range resonant energy transfer for enhanced exciton harvesting for organic solar cells ADVANCED MATERIALS Scully, S. R., Armstrong, P. B., Edder, C., Frechet, J. M., McGehee, M. D. 2007; 19 (19): 2961-?

    View details for DOI 10.1002/adma.200700917

    View details for Web of Science ID 000250394200037

  • COLL 467-Nanotextured transparent semiconductor oxides for energy conversion Zhou, Z., Ko, D., Earl, M. J., Williams, S., Cheng, B., Gowrishankar, V., McGehee, M. D., DeSimone, J., Samulski, E. T. AMER CHEMICAL SOC. 2007

    View details for Web of Science ID 000207593902464

  • COLL 177-Nanopatterning TiO2 for photovoltaic applications Williams, S., Earl, M. J., Zhou, Z., Gowrishankar, V., McGehee, M. D., Samulski, E. T., DeSimone, J. M. AMER CHEMICAL SOC. 2007

    View details for Web of Science ID 000207593902452

  • Effects of molecular interface modification in hybrid organic-inorganic photovoltaic cells JOURNAL OF APPLIED PHYSICS Goh, C., Scully, S. R., McGehee, M. D. 2007; 101 (11)

    View details for DOI 10.1063/1.2737977

    View details for Web of Science ID 000247306000146

  • High-efficiency, Cd-free copper-indium-gallium-diselenide/polymer hybrid solar cells SOLAR ENERGY MATERIALS AND SOLAR CELLS Gowrishankar, V., Luscombe, C. K., McGehee, M. D., Frechet, J. M. 2007; 91 (9): 807-812

    View details for DOI 10.1016/j.solmat.2007.01.012

    View details for Web of Science ID 000246438500009

  • Exciton transport and inorganic/organic photovoltaics McGehee, M. D., Scully, S. R. AMER CHEMICAL SOC. 2007

    View details for Web of Science ID 000207723100552

  • Exciton splitting and carrier transport across the amorphous-silicon/polymer solar cell interface APPLIED PHYSICS LETTERS Gowrishankar, V., Scully, S. R., McGehee, M. D., Wang, Q., Branz, H. M. 2006; 89 (25)

    View details for DOI 10.1063/1.2408641

    View details for Web of Science ID 000243415200043

  • Generalized coating route to silica and titania films with orthogonally tilted cylindrical nanopore arrays NANO LETTERS Koganti, V. R., Dunphy, D., Gowrishankar, V., McGehee, M. D., Li, X., Wang, J., Rankin, S. E. 2006; 6 (11): 2567-2570

    Abstract

    We describe a simple, inexpensive coating method to produce thin silica and titania films with surfactant templated, orthogonally tilted cylindrical nanopore arrays. These films can be deposited onto any substrate because orientation of the 2D hexagonally close packed (HCP) mesophases out of the plane of the film is directed by a chemically neutral sacrificial copolymer layer. Orientation of the HCP mesophases through the entire thickness of films cured in open air is achieved by limiting the coating thickness. This generalizes the coating method by making it possible to deposit oriented films on substrates of any curvature and size. We find a critical thickness between 70 and 100 nm, below which the triblock copolymer surfactant-templated HCP phase aligns completely out of the plane of glass and silicon wafer substrates. Above this thickness, the effect of the chemically neutral bottom layer does not propagate across the entire film, and alignment of the HCP mesophases parallel to the (nonpolar) air interface produces a mixed orientation.

    View details for DOI 10.1021/nl061992v

    View details for Web of Science ID 000241856700031

    View details for PubMedID 17090092

  • PMSE 449-Enhancing the chemical resistance of high fractional free volume vapor-selective polymers McGehee, M. D., Summers, M. A. AMER CHEMICAL SOC. 2006: 276-276

    View details for Web of Science ID 000207781700269

  • PMSE 620-Post-cure reactions in VOMM based thiol-ene UV curable materials Summers, M. A., Scully, S. R., Liu, Y., McGehee, M. D. AMER CHEMICAL SOC. 2006: 344-344

    View details for Web of Science ID 000207781700336

  • Fabrication of densely packed, well-ordered, high-aspect-ratio silicon nanopillars over large areas using block copolymer lithography THIN SOLID FILMS Gowrishankar, V., Miller, N., McGehee, M. D., Misner, M. J., Ryu, D. Y., Russell, T. P., Drockenmuller, E., Hawker, C. J. 2006; 513 (1-2): 289-294

    View details for DOI 10.1016/j.tsf.2006.01.064

    View details for Web of Science ID 000238963600047

  • Effects of optical interference and energy transfer on exciton diffusion length measurements in organic semiconductors JOURNAL OF APPLIED PHYSICS Scully, S. R., McGehee, M. D. 2006; 100 (3)

    View details for DOI 10.1063/1.2226687

    View details for Web of Science ID 000239764100119

  • Organic solar cells with carbon nanotube network electrodes APPLIED PHYSICS LETTERS Rowell, M. W., Topinka, M. A., McGehee, M. D., Prall, H., Dennler, G., Sariciftci, N. S., Hu, L., Gruner, G. 2006; 88 (23)

    View details for DOI 10.1063/1.2209887

    View details for Web of Science ID 000238914500081

  • Resonance energy transfer from organic chromophores to fullerene molecules JOURNAL OF APPLIED PHYSICS Liu, Y., Summers, M. A., Scully, S. R., McGehee, M. D. 2006; 99 (9)

    View details for DOI 10.1063/1.2195890

    View details for Web of Science ID 000237682900041

  • Liquid-crystalline semiconducting polymers with high charge-carrier mobility NATURE MATERIALS McCulloch, I., Heeney, M., Bailey, C., Genevicius, K., MacDonald, I., Shkunov, M., Sparrowe, D., Tierney, S., Wagner, R., Zhang, W. M., Chabinyc, M. L., Kline, R. J., McGehee, M. D., Toney, M. F. 2006; 5 (4): 328-333

    Abstract

    Organic semiconductors that can be fabricated by simple processing techniques and possess excellent electrical performance, are key requirements in the progress of organic electronics. Both high semiconductor charge-carrier mobility, optimized through understanding and control of the semiconductor microstructure, and stability of the semiconductor to ambient electrochemical oxidative processes are required. We report on new semiconducting liquid-crystalline thieno[3,2-b ]thiophene polymers, the enhancement in charge-carrier mobility achieved through highly organized morphology from processing in the mesophase, and the effects of exposure to both ambient and low-humidity air on the performance of transistor devices. Relatively large crystalline domain sizes on the length scale of lithographically accessible channel lengths ( approximately 200 nm) were exhibited in thin films, thus offering the potential for fabrication of single-crystal polymer transistors. Good transistor stability under static storage and operation in a low-humidity air environment was demonstrated, with charge-carrier field-effect mobilities of 0.2-0.6 cm(2) V(-1) s(-1) achieved under nitrogen.

    View details for DOI 10.1038/nmat1612

    View details for Web of Science ID 000236530400025

    View details for PubMedID 16547518

  • Resonance energy transfer in organic photovoltaic devices Summers, M. A., Liu, Y., Scully, S. R., McGehee, M. D. AMER CHEMICAL SOC. 2006

    View details for Web of Science ID 000238125903140

  • Improving organic-inorganic hybrid solar cells with interface modification and energy transfer McGehee, M. D. AMER CHEMICAL SOC. 2006

    View details for Web of Science ID 000238125904815

  • Highly oriented crystals at the buried interface in polythiophene thin-film transistors NATURE MATERIALS Kline, R. J., McGehee, M. D., Toney, M. F. 2006; 5 (3): 222-228

    View details for DOI 10.1038/nmat1590

    View details for Web of Science ID 000235707900022

  • Dependence of band offset and open-circuit voltage on the interfacial interaction between TiO2 and carboxylated polythiophenes JOURNAL OF PHYSICAL CHEMISTRY B Liu, Y. X., Scully, S. R., McGehee, M. D., Liu, J. S., Luscombe, C. K., Frechet, J. M., Shaheen, S. E., Ginley, D. S. 2006; 110 (7): 3257-3261

    Abstract

    The interface of planar TiO(2)/polymer photovoltaic cells was modified with two carboxylated polythiophenes having different densities of carboxylic acid groups. Both of the interface modifiers increase the photocurrent of the cells but lower the open-circuit voltage. The work function of the TiO(2), measured using a Kelvin probe, increases with increasing density of carboxylic acid groups due to the formation of interfacial dipoles pointing toward the TiO(2) surface. The formation of interfacial dipoles results in a shift in the band offset at the TiO(2)/polymer interface, which explains the decrease in the open-circuit voltage. This work demonstrates that care must be taken when using carboxylic acid side groups to attach polymers to titania surfaces in photovoltaic cells. If the density of attachment groups is just enough to attach the polymer, then the benefits of the interface modifier can be realized without substantially decreasing the open-circuit voltage.

    View details for DOI 10.1021/jp056576y

    View details for Web of Science ID 000235560900045

    View details for PubMedID 16494337

  • Morphology and charge transport in conjugated polymer POLYMER REVIEWS Kline, R. J., McGehee, M. D. 2006; 46 (1): 27-45

    View details for DOI 10.1080/15321790500471194

    View details for Web of Science ID 000240473300003

  • Morphology and Charge Transport in Conjugated Polymers (Review Article) Journal of Macromolecular Science - Polymer Reviews Kline, R., J., McGehee, M., D. 2006; 46: 27
  • Using resonance energy transfer to improve exciton harvesting in organic-inorganic hybrid photovoltaic cells ADVANCED MATERIALS Liu, Y. X., Summers, M. A., Edder, C., Frechet, J. M., McGehee, M. D. 2005; 17 (24): 2960-?

    View details for DOI 10.1002/adma.200501307

    View details for Web of Science ID 000234472400008

  • Enhanced hole mobility in regioregular polythiophene infiltrated in straight nanopores ADVANCED FUNCTIONAL MATERIALS Coakley, K. M., Srinivasan, B. S., Ziebarth, J. M., Goh, C., Liu, Y. X., McGehee, M. D. 2005; 15 (12): 1927-1932

    View details for DOI 10.1002/adfm.200500364

    View details for Web of Science ID 000234012900003

  • Synthesis, characterization, and field-effect transistor performance of carboxylate-functionalized polythiophenes with increased air stability CHEMISTRY OF MATERIALS Murphy, A. R., Liu, J. S., Luscombe, C., Kavulak, D., Frechet, J. M., Kline, R. J., McGehee, M. D. 2005; 17 (20): 4892-4899

    View details for DOI 10.1021/cm05091ld

    View details for Web of Science ID 000232326700002

  • Nanostructuring titania by embossing with polymer molds made from anodic alumina templates NANO LETTERS Goh, C., Coakley, K. M., McGehee, M. D. 2005; 5 (8): 1545-1549

    Abstract

    We demonstrate a method for embossing titania sol--gel precursor with poly(methyl methacrylate) (PMMA) molds to make thin films of titania that have dense arrays of 35--65 nm diameter pores, whose features are 1 order of magnitude smaller than those previously demonstrated for sol--gel molding. We show that the high modulus of PMMA is necessary to preserve small features with high aspect ratios on the mold for nanopatterning. The molds are prepared by thermally infiltrating PMMA into anodic alumina templates, whose pore dimensions and depths are adjustable by varying anodization conditions. The difficulties associated with mold release from a master are avoided by wet etching the template. These titania films, and others made with other semiconductors, could be useful for photovoltaic, photocatalytic, and sensing applications where nanostructuring of surfaces with controlled dimensions are essential.

    View details for DOI 10.1021/nl050704c

    View details for Web of Science ID 000231211300004

    View details for PubMedID 16089486

  • Dependence of regioregular poly(3-hexylthiophene) film morphology and field-effect mobility on molecular weight MACROMOLECULES Kline, R. J., McGehee, M. D., Kadnikova, E. N., Liu, J. S., Frechet, J. M., Toney, M. F. 2005; 38 (8): 3312-3319

    View details for DOI 10.1021/ma047415f

    View details for Web of Science ID 000228442100035

  • Molecular-weight-dependent mobilities in regioregular poly(3-hexyl-thiophene) diodes APPLIED PHYSICS LETTERS Goh, C., Kline, R. J., McGehee, M. D., Kadnikova, E. N., Frechet, J. M. 2005; 86 (12)

    View details for DOI 10.1063/1.1891301

    View details for Web of Science ID 000228050900045

  • A theoretical and experimental investigation of light extraction from polymer light-emitting diodes JOURNAL OF APPLIED PHYSICS Ziebarth, J. M., McGehee, M. D. 2005; 97 (6)

    View details for DOI 10.1063/1.1866487

    View details for Web of Science ID 000227767700085

  • Improving exciton and charge transport in organic-inorganic hybrid photovoltaic cells. McGehee, M. D. AMER CHEMICAL SOC. 2005: U1151-U1151

    View details for Web of Science ID 000235066605310

  • Structural correlations of charge transport in regioregular poly(3-hexylthiophene). Kline, R. J., McGehee, M. D., Toney, M. F. AMER CHEMICAL SOC. 2005: U1156-U1156

    View details for Web of Science ID 000235066605340

  • Ordered Organic-Inorganic Bulk Heterojunction Photovoltaic Cells Materials Research Society Bulletin Coakley, K., M., Liu, Y., Goh, C., McGehee, M., D. 2005; 30: 37
  • Conjugated polymer photovoltaic cells CHEMISTRY OF MATERIALS Coakley, K. M., McGehee, M. D. 2004; 16 (23): 4533-4542

    View details for DOI 10.1021/cm049654n

    View details for Web of Science ID 000225078600015

  • Effect of co-catalyst on the polymerization of alpha-olefin monomers by (cyclopentadienyl)(nitroxide)titanium(IV) complexes. Dove, A. P., Mahanthappa, M. K., Waymouth, R. M. AMER CHEMICAL SOC. 2004: U424-U424

    View details for Web of Science ID 000223655702187

  • Polythiophene containing thermally removable solubilizing groups enhances the interface and the performance of polymer-titania hybrid solar cells JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Liu, J. S., Kadnikova, E. N., Liu, Y. X., McGehee, M. D., Frechet, J. M. 2004; 126 (31): 9486-9487

    Abstract

    A polythiophene derivative containing thermally removable branched ester solubilizing groups has been prepared and tested as a processable organic semiconductor polymer with tunable electronic and chemical properties for hybrid polymer-inorganic solar cells. Thermal removal of the protecting group enhances the interface between the organic and inorganic components while also contributing to better light absorption, energy transfer, and overall cell performance.

    View details for DOI 10.1021/ja047452m

    View details for Web of Science ID 000223110100010

    View details for PubMedID 15291521

  • Extracting light from polymer light-emitting diodes using stamped Bragg gratings ADVANCED FUNCTIONAL MATERIALS Ziebarth, J. M., Saafir, A. K., Fan, S., McGehee, M. D. 2004; 14 (5): 451-456

    View details for DOI 10.1002/adfm.200305070

    View details for Web of Science ID 000221707700006

  • Molecular weight dependent mobilities in regioregular poly(3-hexyl-thiophene) diodes and transistors Goh, C. T., Kline, R. J., McGehee, M. D., Kadnikova, E. N., Liu, J. S., Frechet, J. M. AMER CHEMICAL SOC. 2004: U425-U425

    View details for Web of Science ID 000223655702189

  • Electropolymerization of conjugated polymers in mesoporous titania for photovoltaic applications ORGANIC PHOTOVOLTAICS IV Liu, Y. X., Coakley, K. M., McGehee, M. D. 2004; 5215: 187-194

    View details for Web of Science ID 000189442000021

  • Measuring the refractive indices of conjugated polymer films with Bragg grating outcouplers APPLIED PHYSICS LETTERS Ziebarth, J. M., McGehee, M. D. 2003; 83 (24): 5092-5094

    View details for DOI 10.1063/1.1633964

    View details for Web of Science ID 000187181400066

  • Photovoltaic cells made from conjugated polymers infiltrated into mesoporous titania APPLIED PHYSICS LETTERS Coakley, K. M., McGehee, M. D. 2003; 83 (16): 3380-3382

    View details for DOI 10.1063/1.1616197

    View details for Web of Science ID 000185954400050

  • Controlling the field-effect mobility of regioregular polythiophene by changing the molecular weight ADVANCED MATERIALS Kline, R. J., McGehee, M. D., Kadnikova, E. N., Liu, J. S., Frechet, J. M. 2003; 15 (18): 1519-?

    View details for DOI 10.1002/adma.200305275

    View details for Web of Science ID 000185399500003

  • Reduced operating voltages in polymer light-emitting diodes doped with rare-earth complexes ADVANCED MATERIALS Robinson, M. R., Ostrowski, J. C., Bazan, G. C., McGehee, M. D. 2003; 15 (18): 1547-?

    View details for DOI 10.1002/adma.200304651

    View details for Web of Science ID 000185399500012

  • Infiltrating semiconducting polymers into self-assembled mesoporous titania films for photovoltaic applications ADVANCED FUNCTIONAL MATERIALS Coakley, K. M., Liu, Y. X., McGehee, M. D., Frindell, K. L., Stucky, G. D. 2003; 13 (4): 301-306

    View details for DOI 10.1002/adfm.200304361

    View details for Web of Science ID 000182549100007

  • Dye-doped mesostructured silica as a distributed feedback laser fabricated by soft lithography ADVANCED MATERIALS Scott, B. J., Wirnsberger, G., McGehee, M. D., Chmelka, B. F., Stucky, G. D. 2001; 13 (16): 1231-1234

    View details for Web of Science ID 000170902600002

  • Dye-doped mesostructured nanocomposites as laser materials. Scott, B. J., McGehee, M. D., Wirnsberger, G., Chmelka, B. F., Stucky, G. D. AMER CHEMICAL SOC. 2001: U739-U739

    View details for Web of Science ID 000168824704704

  • Semiconducting (conjugated) polymers as materials for solid-state lasers ADVANCED MATERIALS McGehee, M. D., Heeger, A. J. 2000; 12 (22): 1655-1668

    View details for Web of Science ID 000166011800002

  • Mirrorless Lasing from Mesostructured Waveguides Patterned by Soft Lithography Science Yang, P., Wirnsberger, G., Huang, H., C., Cordero, S., R., McGehee, M., D., Scott, B. 2000; 287: 465
  • Forster transfer based amplified spontaneous emission in conjugated polymer blends SYNTHETIC METALS Gupta, R., Stevenson, M., McGehee, M. D., Dogariu, A., Srdanov, V., Park, J. Y., Heeger, A. J. 1999; 102 (1-3): 875-876

    View details for Web of Science ID 000081056400007

  • Index of refraction and waveguiding in thin films of a conjugated polymer which exhibits stimulated emission SYNTHETIC METALS Miller, E. K., McGehee, M. D., Diaz-Garcia, M., Srikant, V., Heeger, A. J. 1999; 102 (1-3): 1091-1092

    View details for Web of Science ID 000081056400108

  • Characterization of semiconducting polymer laser materials and the prospects for diode lasers SYNTHETIC METALS McGehee, M. D., Gupta, R., Miller, E. K., Heeger, A. J. 1999; 102 (1-3): 1030-1033

    View details for Web of Science ID 000081056400082

  • Narrow Bandwidth Luminescence from Blends with Energy Transfer from Semiconducting Conjugated Polymers to Europium Complexes Advanced Materials McGehee, M., D., Bergstedt, T., Saab, A., P., Zhang, C., O'Regan, M., Bazan, G. 1999; 11: 1349
  • Doped Mesoporous Silica Fibers: A New Laser Material Advanced Materials Marlow, F., McGehee, M., D., Zhao, D., Chmelka, B., F., Stucky, G., D. 1999; 11: 632
  • Semiconducting Polymer Distributed Feedback Lasers Applied Physics Letters McGehee, M., D., Diaz-Garcia, M., A., Hide, F., Gupta, R., Miller, E., K., Moses, D. 1998; 72: 1536
  • Experimental indication of a naphthalene-base molecular aggregate for the carrier of the 2175 angstrom interstellar extinction feature ASTROPHYSICAL JOURNAL Beegle, L. W., Wdowiak, T. J., Robinson, M. S., Cronin, J. R., McGehee, M. D., Clemett, S. J., Gillette, S. 1997; 487 (2): 976-982

    Abstract

    Experiments where the simple polycyclic aromatic hydrocarbon (PAH) naphthalene (C10H8) is subjected to the energetic environment of a plasma have resulted in the synthesis of a molecular aggregate that has ultraviolet spectral characteristics that suggest it provides insight into the nature of the carrier of the 2175 angstroms interstellar extinction feature and may be a laboratory analog. Ultraviolet, visible, infrared, and mass spectroscopy, along with gas chromatography, indicate that it is a molecular aggregate in which an aromatic double ring ("naphthalene") structural base serves as the electron "box" chromophore that gives rise to the envelope of the 2175 angstroms feature. This chromophore can also provide the peak of the feature or function as a mantle in concert with another peak provider such as graphite. The molecular base/chromophore manifests itself both as a structural component of an alkyl-aromatic polymer and as a substructure of hydrogenated PAH species. Its spectral and molecular characteristics are consistent with what is generally expected for a complex molecular aggregate that has a role as an interstellar constituent.

    View details for Web of Science ID A1997YA04000045

    View details for PubMedID 11540492

  • Microplanar polymer light-emitting diodes SYNTHETIC METALS McGehee, M. D., Vacar, D., Lemmer, U., Moses, D., Heeger, A. J. 1997; 85 (1-3): 1233-1234

    View details for Web of Science ID A1997WX70800088

  • Light emission from semiconducting polymers: LEDS, lasers, and white light for the future ORGANIC LIGHT-EMITTING MATERIALS AND DEVICES Hide, F., Diaz-Garcia, M. A., McGehee, M. D., Schwartz, B. J., Kozodoy, P., DenBaars, S. P., Heeger, A. J. 1997; 3148: 22-33

    View details for Web of Science ID 000071859600003