Alberto Salleo

All Publications

• One-Step Macroscopic Alignment of Conjugated Polymer Systems by Epitaxial Crystallization during Spin-Coating ADVANCED FUNCTIONAL MATERIALS Muller, C., Aghamohammadi, M., Himmelberger, S., Sonar, P., Garriga, M., Salleo, A., Campoy-Quiles, M. 2013; 23 (19): 2368-2377

  View details for DOI 10.1002/adfm.201202983

  View details for Web of Science ID 000318808800003

• The chemical and structural origin of efficient p-type doping in P3HT ORGANIC ELECTRONICS Duong, D. T., Wang, C., Antono, E., Toney, M. F., Salleo, A. 2013; 14 (5): 1330-1336

  View details for DOI 10.1016/j.orgel.2013.02.028

  View details for Web of Science ID 000317825800017

• Ultrathin Body Poly(3-hexylthiophene) Transistors with Improved Short-Channel Performance ACS APPLIED MATERIALS & INTERFACES Wang, C., Rivnay, J., Himmelberger, S., Vakhshouri, K., Toney, M. F., Gomez, E. D., Salleo, A. 2013; 5 (7): 2342-2346

  Abstract

  The microstructure and charge transport properties of binary blends of regioregular (rr) and regiorandom (RRa) poly(3-hexylthiophene) (P3HT) are investigated. X-ray diffraction of the blended films is consistent with a vertically separated structure, with rr-P3HT preferentially crystallizing at the semiconductor/dielectric interface. Thin film transistors made with these blended films preserve high field effect mobility with rr-P3HTcontent as low as 5.6%. In these dilute blends, we estimate that the thickness of rr-P3HT in the channel is only a few nanometers. Significantly, as a result of such an ultrathin active layer at the interface, short channel effects due to bulk currents are eliminated, suggesting a new route to fabricate high-performance, short-channel, and reliable organic electronic devices.

  View details for DOI 10.1021/am3027103

  View details for Web of Science ID 000317549100008

• Vertical Confinement and Interface Effects on the Microstructure and Charge Transport of P3HT Thin Films JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS Jimison, L. H., Himmelberger, S., Duong, D. T., Rivnay, J., Toney, M. F., Salleo, A. 2013; 51 (7): 611-620

  View details for DOI 10.1002/polb.23265

  View details for Web of Science ID 000315860100015

• Low-Temperature Processed Ga-Doped ZnO Coatings from Colloidal Inks JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Della Gaspera, E., Bersani, M., Cittadini, M., Guglielmi, M., Pagani, D., Noriega, R., Mehra, S., Salleo, A., Martucci, A. 2013; 135 (9): 3439-3448

  Abstract

  We present a new colloidal synthesis of gallium-doped zinc oxide nanocrystals that are transparent in the visible and absorb in the near-infrared. Thermal decomposition of zinc stearate and gallium nitrate after hot injection of the precursors in a mixture of organic amines leads to nanocrystals with tunable properties according to gallium amount. Substitutional Ga(3+) ions trigger a plasmonic resonance in the infrared region resulting from an increase in the free electrons concentration. These nanocrystals can be deposited by spin coating, drop casting, and spray coating resulting in homogeneous and high-quality thin films. The optical transmission of the Ga-ZnO nanoparticle assemblies in the visible is greater than 90%, and at the same time, the near-infrared absorption of the nanocrystals is maintained in the films as well. Several strategies to improve the films electrical and optical properties have been presented, such as UV treatments to remove the organic compounds responsible for the observed interparticle resistance and reducing atmosphere treatments on both colloidal solutions and thin films to increase the free carriers concentration, enhancing electrical conductivity and infrared absorption. The electrical resistance of the nanoparticle assemblies is about 30 k?/sq for the as-deposited, UV-exposed films, and it drops down to 300 ?/sq after annealing in forming gas at 450 °C, comparable with state of the art tin-doped indium oxide coatings deposited from nanocrystal inks.

  View details for DOI 10.1021/ja307960z

  View details for Web of Science ID 000315936700032

  View details for PubMedID 23394063

• Moderate doping leads to high performance of semiconductor/insulator polymer blend transistors NATURE COMMUNICATIONS Lu, G., Blakesley, J., Himmelberger, S., Pingel, P., Frisch, J., Lieberwirth, I., Salzmann, I., Oehzelt, M., Di Pietro, R., Salleo, A., Koch, N., Neher, D. 2013; 4

  Abstract

  Polymer transistors are being intensively developed for next-generation flexible electronics. Blends comprising a small amount of semiconducting polymer mixed into an insulating polymer matrix have simultaneously shown superior performance and environmental stability in organic field-effect transistors compared with the neat semiconductor. Here we show that such blends actually perform very poorly in the undoped state, and that mobility and on/off ratio are improved dramatically upon moderate doping. Structural investigations show that these blend layers feature nanometre-scale semiconductor domains and a vertical composition gradient. This particular morphology enables a quasi three-dimensional spatial distribution of semiconductor pathways within the insulating matrix, in which charge accumulation and depletion via a gate bias is substantially different from neat semiconductor, and where high on-current and low off-current are simultaneously realized in the stable doped state. Adding only 5?wt% of a semiconducting polymer to a polystyrene matrix, we realized an environmentally stable inverter with gain up to 60.

  View details for DOI 10.1038/ncomms2587

  View details for Web of Science ID 000318873900042

  View details for PubMedID 23481396

• 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

• Solution processed zinc oxide nanopyramid/silver nanowire transparent network films with highly tunable light scattering properties NANOSCALE Mehra, S., Christoforo, M. G., Peumans, P., Salleo, A. 2013; 5 (10): 4400-4403

  Abstract

  Metal nanowire transparent networks are promising replacements to indium tin oxide (ITO) transparent electrodes for optoelectronic devices. While the transparency and sheet resistance are key metrics for transparent electrode performance, independent control of the film light scattering properties is important to developing multifunctional electrodes for improved photovoltaic absorption. Here we show that controlled incorporation of ZnO nanopyramids into a metal nanowire network film affords independent, highly tunable control of the scattering properties (haze) with minimal effects on the transparency and sheet resistance. Varying the zinc oxide/silver nanostructure ratios prior to spray deposition results in sheet resistances, transmission (600 nm), and haze (600 nm) of 6-30 Ω □(-1), 68-86%, and 34-66%, respectively. Incorporation of zinc oxide nanopyramid scattering agents into the conducting nanowire mesh has a negligible effect on mesh connectivity, providing a straightforward method of controlling electrode scattering properties. The decoupling of the film scattering power and electrical characteristics makes these films promising candidates for highly scattering transparent electrodes in optoelectronic devices and can be generalized to other metal nanowire films as well as carbon nanotube transparent electrodes.

  View details for DOI 10.1039/c3nr00863k

  View details for Web of Science ID 000318362400052

• Solution processed zinc oxide nanopyramid/silver nanowire transparent network films with highly tunable light scattering properties Nanoscale Mehra, S., Christoforo, M., G., Peumans, P., Salleo, A. 2013; 5: 4400
• Efficient charge generation by relaxed charge-transfer states at organic interfaces Nature Materials, Advance Online Vandewal, K., Albrecht, S., Hoke, E., T., Graham, K., R., Widmer, J., Douglas, J., D., Salleo, A. 2013
• High Mobility N-Type Transistors Based on Solution-Sheared Doped 6,13-Bis(triisopropylsilylethynyl)pentacene Thin Films Advanced Materials Naab, B., D., Himmelberger, S., Diao, Y., Vandewal, K., Wei, P., Lussem, B., Salleo, A. 2013; 25: 4663
• Color in the corners: ITO-free white OLEDs with angular color stability Advanced Materials Gaynor, W., Hofmann, S., Christoforo, G., M., Sachse, C., Mehra, S., Salleo, A. 2013; 25: 4006
• Role of confinement and aggregation in charge transport in semicrystalline polythiophene thin films PHYSICAL REVIEW B Duong, D. T., Toney, M. F., Salleo, A. 2012; 86 (20)

  View details for DOI 10.1103/PhysRevB.86.205205

  View details for Web of Science ID 000311537400002

• Quantitative Determination of Organic Semiconductor Microstructure from the Molecular to Device Scale CHEMICAL REVIEWS Rivnay, J., Mannsfeld, S. C., Miller, C. E., Salleo, A., Toney, M. F. 2012; 112 (10): 5488-5519

  View details for DOI 10.1021/cr3001109

  View details for Web of Science ID 000309628100012

  View details for PubMedID 22877516

• Estimation of the spatial distribution of traps using space-charge-limited current measurements in an organic single crystal PHYSICAL REVIEW B Dacuna, J., Xie, W., Salleo, A. 2012; 86 (11)

  View details for DOI 10.1103/PhysRevB.86.115202

  View details for Web of Science ID 000308392800002

• Optically switchable transistor via energy-level phototuning in a bicomponent organic semiconductor NATURE CHEMISTRY Orgiu, E., Crivillers, N., Herder, M., Grubert, L., Paetzel, M., Frisch, J., Pavlica, E., Duong, D. T., Bratina, G., Salleo, A., Koch, N., Hecht, S., Samori, P. 2012; 4 (8): 675-679

  Abstract

  Organic semiconductors are suitable candidates for printable, flexible and large-area electronics. Alongside attaining an improved device performance, to confer a multifunctional nature to the employed materials is key for organic-based logic applications. Here we report on the engineering of an electronic structure in a semiconducting film by blending two molecular components, a photochromic diarylethene derivative and a poly(3-hexylthiophene) (P3HT) matrix, to attain phototunable and bistable energy levels for the P3HT's hole transport. As a proof-of-concept we exploited this blend as a semiconducting material in organic thin-film transistors. The device illumination at defined wavelengths enabled reversible tuning of the diarylethene's electronic states in the blend, which resulted in modulation of the output current. The device photoresponse was found to be in the microsecond range, and thus on a technologically relevant timescale. This modular blending approach allows for the convenient incorporation of various molecular components, which opens up perspectives on multifunctional devices and logic circuits.

  View details for DOI 10.1038/NCHEM.1384

  View details for Web of Science ID 000306696300019

  View details for PubMedID 22824901

• Scalable Fabrication of Strongly Textured Organic Semiconductor Micropatterns by Capillary Force Lithography ADVANCED MATERIALS Jo, P. S., Vailionis, A., Park, Y. M., Salleo, A. 2012; 24 (24): 3269-3274

  Abstract

  Strongly textured organic semiconductor micropatterns made of the small molecule dioctylbenzothienobenzothiophene (C(8)-BTBT) are fabricated by using a method based on capillary force lithography (CFL). This technique provides the C(8)-BTBT solution with nucleation sites for directional growth, and can be used as a scalable way to produce high quality crystalline arrays in desired regions of a substrate for OFET applications.

  View details for DOI 10.1002/adma.201200524

  View details for Web of Science ID 000305450500017

  View details for PubMedID 22605625

• Electrothermal phenomena in zinc oxide nanowires and contacts APPLIED PHYSICS LETTERS LeBlanc, S., Phadke, S., Kodama, T., Salleo, A., Goodson, K. E. 2012; 100 (16)

  View details for DOI 10.1063/1.4703935

  View details for Web of Science ID 000303128500048

• A Selenophene-Based Low-Bandgap Donor-Acceptor Polymer Leading to Fast Ambipolar Logic ADVANCED MATERIALS Kronemeijer, A. J., Gili, E., Shahid, M., Rivnay, J., Salleo, A., Heeney, M., Sirringhaus, H. 2012; 24 (12): 1558-1565

  Abstract

  Fast ambipolar CMOS-like logic is demonstrated using a new selenophene-based donor-acceptor polymer semiconductor. The polymer exhibits saturation hole and electron mobilities of 0.46 cm(2) /Vs and 0.84 cm(2) /Vs. Inverters are fabricated with high gains while three-stage ring oscillators show stable oscillation with an unprecedented maximum frequency of 182 kHz at a relatively low supply voltage of 50 V.

  View details for DOI 10.1002/adma.201104522

  View details for Web of Science ID 000301523600007

  View details for PubMedID 22351605

• Controlled Conjugated Backbone Twisting for an Increased Open-Circuit Voltage while Having a High Short-Circuit Current in Poly(hexylthiophene) Derivatives JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Ko, S., Hoke, E. T., Pandey, L., Hong, S., Mondal, R., Risko, C., Yi, Y., Noriega, R., McGehee, M. D., Bredas, J., Salleo, A., Bao, Z. 2012; 134 (11): 5222-5232

  Abstract

  Conjugated polymers with nearly planar backbones have been the most commonly investigated materials for organic-based electronic devices. More twisted polymer backbones have been shown to achieve larger open-circuit voltages in solar cells, though with decreased short-circuit current densities. We systematically impose twists within a family of poly(hexylthiophene)s and examine their influence on the performance of polymer:fullerene bulk heterojunction (BHJ) solar cells. A simple chemical modification concerning the number and placement of alkyl side chains along the conjugated backbone is used to control the degree of backbone twisting. Density functional theory calculations were carried out on a series of oligothiophene structures to provide insights on how the sterically induced twisting influences the geometric, electronic, and optical properties. Grazing incidence X-ray scattering measurements were performed to investigate how the thin-film packing structure was affected. The open-circuit voltage and charge-transfer state energy of the polymer:fullerene BHJ solar cells increased substantially with the degree of twist induced within the conjugated backbone--due to an increase in the polymer ionization potential--while the short-circuit current decreased as a result of a larger optical gap and lower hole mobility. A controlled, moderate degree of twist along the poly(3,4-dihexyl-2,2':5',2''-terthiophene) (PDHTT) conjugated backbone led to a 19% enhancement in the open-circuit voltage (0.735 V) vs poly(3-hexylthiophene)-based devices, while similar short-circuit current densities, fill factors, and hole-carrier mobilities were maintained. These factors resulted in a power conversion efficiency of 4.2% for a PDHTT:[6,6]-phenyl-C(71)-butyric acid methyl ester (PC(71)BM) blend solar cell without thermal annealing. This simple approach reveals a molecular design avenue to increase open-circuit voltage while retaining the short-circuit current.

  View details for DOI 10.1021/ja210954r

  View details for Web of Science ID 000302191900036

  View details for PubMedID 22385287

• 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

• Effect of Miscibility and Percolation on Electron Transport in Amorphous Poly(3-Hexylthiophene)/Phenyl-C-61-Butyric Acid Methyl Ester Blends PHYSICAL REVIEW LETTERS Vakhshouri, K., Kozub, D. R., Wang, C., Salleo, A., Gomez, E. D. 2012; 108 (2)

  Abstract

  Recent evidence has demonstrated that amorphous mixed phases are ubiquitous within mesostructured polythiophene-fullerene mixtures. Nevertheless, the role of mixing within nanophases on charge transport of organic semiconductor mixtures is not fully understood. To this end, we have examined the electron mobility in amorphous blends of poly(3-hexylthiophene) and phenyl-C(61)-butyric acid methyl ester. Our studies reveal that the miscibility of the components strongly affects electron transport within blends. Immiscibility promotes efficient electron transport by promoting percolating pathways within organic semiconductor mixtures. As a consequence, partial miscibility may be important for efficient charge transport in polythiophene-fullerene mixtures and organic solar cell performance.

  View details for DOI 10.1103/PhysRevLett.108.026601

  View details for Web of Science ID 000298991400022

  View details for PubMedID 22324702

• Electrothermal phenomena in zinc oxide nanowires and contacts Appl. Phys. Lett. LeBlanc, S., Phadke, S., Kodama, T., Salleo, A., Goodson, K., E. 2012; 100: 163105
• Solution-grown n-type ZnO nanostructures: synthesis, microstructure and doping Handbook of ZnO and Related Materials Noriega, R., Mehra, S., Salleo, A. edited by Feng, Z., C. Taylor and Francis/CRC Press. 2012: 1
• Controlled conjugated backbone twisting for an increased open-circuit voltage while having a high short-circuit current in poly(hexyl)thiophene derivatives J. Am. Chem. Soc. Ko, S., Hoke, E., Pandey, L., Hong, S., Mondal, R., Rajib, R., Salleo, A. 2012; 134: 5222
• Effect of Miscibility and Percolation on Electron Transport in Amorphous Poly(3-Hexylthiophene)/Phenyl-C61-Butyric Acid Methyl Ester Blends Phys. Rev. Lett. Vakhshouri, K., Kozub, D., R., Wang, C., Salleo, A., Gomez, E., D. 2012; 108: 26601
• Title: Using Alignment and 2D Network Simulations to Study Charge Transport Through Doped ZnO Nanowire Thin Film Electrodes ADVANCED FUNCTIONAL MATERIALS Phadke, S., Lee, J., West, J., Peumans, P., Salleo, A. 2011; 21 (24): 4691-4697

  View details for DOI 10.1002/adfm.201100873

  View details for Web of Science ID 000298017900011

• Modeling space-charge-limited currents in organic semiconductors: Extracting trap density and mobility PHYSICAL REVIEW B Dacuna, J., Salleo, A. 2011; 84 (19)

  View details for DOI 10.1103/PhysRevB.84.195209

  View details for Web of Science ID 000297414500029

• Relation between Microstructure and Charge Transport in Polymers of Different Regioregularity JOURNAL OF PHYSICAL CHEMISTRY C McMahon, D. P., Cheung, D. L., Goris, L., Dacuna, J., Salleo, A., Troisi, A. 2011; 115 (39): 19386-19393

  View details for DOI 10.1021/jp207026s

  View details for Web of Science ID 000295245500060

• 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

• Real-Time Observation of Poly(3-alkylthiophene) Crystallization and Correlation with Transient Optoelectronic Properties MACROMOLECULES Boudouris, B. W., Ho, V., Jimison, L. H., Toney, M. F., Salleo, A., Segalman, R. A. 2011; 44 (17): 6653-6658

  View details for DOI 10.1021/ma201316a

  View details for Web of Science ID 000294585600006

• Effect of Acene Length on Electronic Properties in 5-, 6-, and 7-Ringed Heteroacenes ADVANCED MATERIALS Goetz, K. P., Li, Z., Ward, J. W., Bougher, C., Rivnay, J., Smith, J., Conrad, B. R., Parkin, S. R., Anthopoulos, T. D., Salleo, A., Anthony, J. E., Jurchescu, O. D. 2011; 23 (32): 3698-?

  View details for DOI 10.1002/adma.201101619

  View details for Web of Science ID 000294977300012

  View details for PubMedID 21732562

• Steric Control of the Donor/Acceptor Interface: Implications in Organic Photovoltaic Charge Generation JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Holcombe, T. W., Norton, J. E., Rivnay, J., Woo, C. H., Goris, L., Piliego, C., Griffini, G., Sellinger, A., Bredas, J., Salleo, A., Frechet, J. M. 2011; 133 (31): 12106-12114

  Abstract

  The performance of organic photovoltaic (OPV) devices is currently limited by modest short-circuit current densities. Approaches toward improving this output parameter may provide new avenues to advance OPV technologies and the basic science of charge transfer in organic semiconductors. This work highlights how steric control of the charge separation interface can be effectively tuned in OPV devices. By introducing an octylphenyl substituent onto the investigated polymer backbones, the thermally relaxed charge-transfer state, and potentially excited charge-transfer states, can be raised in energy. This decreases the barrier to charge separation and results in increased photocurrent generation. This finding is of particular significance for nonfullerene OPVs, which have many potential advantages such as tunable energy levels and spectral breadth, but are prone to poor exciton separation efficiencies. Computational, spectroscopic, and synthetic methods were combined to develop a structure-property relationship that correlates polymer substituents with charge-transfer state energies and, ultimately, device efficiencies.

  View details for DOI 10.1021/ja203235z

  View details for Web of Science ID 000293768400055

  View details for PubMedID 21688785

• Drastic Control of Texture in a High Performance n-Type Polymeric Semiconductor and Implications for Charge Transport MACROMOLECULES Rivnay, J., Steyrleuthner, R., Jimison, L. H., Casadei, A., Chen, Z., Toney, M. F., Facchetti, A., Neher, D., Salleo, A. 2011; 44 (13): 5246-5255

  View details for DOI 10.1021/ma200864s

  View details for Web of Science ID 000292417800024

• Quantitative analysis of lattice disorder and crystallite size in organic semiconductor thin films PHYSICAL REVIEW B Rivnay, J., Noriega, R., Kline, R. J., Salleo, A., Toney, M. F. 2011; 84 (4)

  View details for DOI 10.1103/PhysRevB.84.045203

  View details for Web of Science ID 000292512800005

• A Boltzmann-weighted hopping model of charge transport in organic semicrystalline films JOURNAL OF APPLIED PHYSICS Kwiatkowski, J. J., Jimison, L. H., Salleo, A., Spakowitz, A. J. 2011; 109 (11)

  View details for DOI 10.1063/1.3594686

  View details for Web of Science ID 000292214700082

• Structural origin of gap states in semicrystalline polymers and the implications for charge transport PHYSICAL REVIEW B Rivnay, J., Noriega, R., Northrup, J. E., Kline, R. J., Toney, M. F., Salleo, A. 2011; 83 (12)

  View details for DOI 10.1103/PhysRevB.83.121306

  View details for Web of Science ID 000288447600001

• Room-Temperature Fabrication of Ultrathin Oxide Gate Dielectrics for Low-Voltage Operation of Organic Field-Effect Transistors ADVANCED MATERIALS Park, Y. M., Daniel, J., Heeney, M., Salleo, A. 2011; 23 (8): 971-974

  View details for DOI 10.1002/adma.201003641

  View details for Web of Science ID 000287669000003

  View details for PubMedID 21341309

• Using Alignment and 2D Network Simulations to Study Charge Transport Through Doped ZnO Nanowire Thin Film Electrodes Advanced Functional Materials Phadke, S., Lee, J., Y., West, J., Peumans, P., Salleo, A. 2011; 21: 4691
• Room-Temerature Fabrication of Ultra-Thin Oxide Gate Dielectrics for Low-Voltage Operation of Organic Field Effect Transistors Advanced Materials Park, Y., M., Daniel, J., Heeney, M., Salleo, A. 2011; 23: 971
• Organic Semiconductors in Transistor Applications Organic Electronics Vol.II: More Materials and Applications James, D., Smith, D., Heeney, M., Anthopoulos, T., Salleo, A., McCulloch, I. edited by Klauk, H. Wiley-VCH Verlag. 2011: 1
• Charge Transport Theories in Organic Semiconductors Organic Electronics Vol.II: More Materials and Applications Noriega, R., Salleo, A. edited by Klauk, H. Wiley-VCH Verlag. 2011: 1
• Laser-Synthesized Epitaxial Graphene ACS NANO Lee, S., Toney, M. F., Ko, W., Randel, J. C., Jung, H. J., Munakata, K., Lu, J., Geballe, T. H., Beasley, M. R., Sinclair, R., Manoharan, H. C., Salleo, A. 2010; 4 (12): 7524-7530

  Abstract

  Owing to its unique electronic properties, graphene has recently attracted wide attention in both the condensed matter physics and microelectronic device communities. Despite intense interest in this material, an industrially scalable graphene synthesis process remains elusive. Here, we demonstrate a high-throughput, low-temperature, spatially controlled and scalable epitaxial graphene (EG) synthesis technique based on laser-induced surface decomposition of the Si-rich face of a SiC single-crystal. We confirm the formation of EG on SiC as a result of excimer laser irradiation by using reflection high-energy electron diffraction (RHEED), Raman spectroscopy, synchrotron-based X-ray diffraction, transmission electron microscopy (TEM), and scanning tunneling microscopy (STM). Laser fluence controls the thickness of the graphene film down to a single monolayer. Laser-synthesized graphene does not display some of the structural characteristics observed in EG grown by conventional thermal decomposition on SiC (0001), such as Bernal stacking and surface reconstruction of the underlying SiC surface.

  View details for DOI 10.1021/nn101796e

  View details for Web of Science ID 000285449100060

  View details for PubMedID 21121692

• Unconventional Face-On Texture and Exceptional In-Plane Order of a High Mobility n-Type Polymer ADVANCED MATERIALS Rivnay, J., Toney, M. F., Zheng, Y., Kauvar, I. V., Chen, Z., Wagner, V., Facchetti, A., Salleo, A. 2010; 22 (39): 4359-?

  Abstract

  Substantial in-plane crystallinity and dominant face-on stacking are observed in thin films of a high-mobility n-type rylene-thiophene copolymer. Spun films of the polymer, previously thought to have little or no order are found to exhibit an ordered microstructure at both interfaces, and in the bulk. The implications of this type of packing and crystalline morphology are discussed as they relate to thin-film transistors.

  View details for DOI 10.1002/adma.201001202

  View details for Web of Science ID 000284000700005

  View details for PubMedID 20623753

• Microstructural Characterization and Charge Transport in Thin Films of Conjugated Polymers ADVANCED MATERIALS Salleo, A., Kline, R. J., Delongchamp, D. M., Chabinyc, M. L. 2010; 22 (34): 3812-3838

  Abstract

  The performance of semiconducting polymers has been steadily increasing in the last 20 years. Improved control over the microstructure of these materials and a deeper understanding of how the microstructure affects charge transport are partially responsible for such trend. The development and widespread use of techniques that allow to characterize the microstructure of semiconducting polymers is therefore instrumental for the advance of these materials. This article is a review of the characterization techniques that provide information used to enhance the understanding of structure/property relationships in semiconducting polymers. In particular, the applications of optical and X-ray spectroscopy, X-ray diffraction, and scanning probe techniques in this context are described.

  View details for DOI 10.1002/adma.200903712

  View details for Web of Science ID 000282793600005

  View details for PubMedID 20607787

• 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

• Quantification of Thin Film Crystallographic Orientation Using X-ray Diffraction with an Area Detector LANGMUIR Baker, J. L., Jimison, L. H., Mannsfeld, S., Volkman, S., Yin, S., Subramanian, V., Salleo, A., Alivisatos, A. P., Toney, M. F. 2010; 26 (11): 9146-9151

  Abstract

  As thin films become increasingly popular (for solar cells, LEDs, microelectronics, batteries), quantitative morphological and crystallographic information is needed to predict and optimize the film's electrical, optical, and mechanical properties. This quantification can be obtained quickly and easily with X-ray diffraction using an area detector in two sample geometries. In this paper, we describe a methodology for constructing complete pole figures for thin films with fiber texture (isotropic in-plane orientation). We demonstrate this technique on semicrystalline polymer films, self-assembled nanoparticle semiconductor films, and randomly packed metallic nanoparticle films. This method can be immediately implemented to help understand the relationship between film processing and microstructure, enabling the development of better and less expensive electronic and optoelectronic devices.

  View details for DOI 10.1021/la904840q

  View details for Web of Science ID 000277928100199

  View details for PubMedID 20361783

• Probing the electrical properties of highly-doped Al:ZnO nanowire ensembles JOURNAL OF APPLIED PHYSICS Noriega, R., Rivnay, J., Goris, L., Kaelblein, D., Klauk, H., Kern, K., Thompson, L. M., Palke, A. C., Stebbins, J. F., Jokisaari, J. R., Kusinski, G., Salleo, A. 2010; 107 (7)

  View details for DOI 10.1063/1.3360930

  View details for Web of Science ID 000276795400081

• Transmission electron microscopy of solution-processed, intrinsic and Al-doped ZnO nanowires for transparent electrode fabrication Kusinski, G. J., Jokisaari, J. R., Noriega, R., Goris, L., Donovan, M., Salleo, A. WILEY-BLACKWELL. 2010: 443-449

  Abstract

  A solution-based chemistry was used to synthesize intrinsic and Al-doped (1% and 5% nominal atomic concentration of Al) ZnO nanostructures. The nanowires were grown at 300 degrees C in trioctylamine by dissolving Zn acetate and Al acetate. Different doping conditions gave rise to different nanoscale morphologies. The effect of a surfactant (oleic acid) was also investigated. An electron microscopy study correlating morphology, aspect ratio and doping of the individual ZnO wires to the electrical properties of the spin coated films is presented. HRTEM revealed single crystalline [0001] wires.

  View details for DOI 10.1111/j.1365-2818.2009.03289.x

  View details for Web of Science ID 000274551700047

  View details for PubMedID 20500415

• Materials and Applications for Large Area Electronics: Solution-Based Approaches CHEMICAL REVIEWS Arias, A. C., MacKenzie, J. D., McCulloch, I., Rivnay, J., Salleo, A. 2010; 110 (1): 3-24

  View details for DOI 10.1021/cr900150b

  View details for Web of Science ID 000274255700002

  View details for PubMedID 20070114

• Materials and Applications for Large-Area Electronics: Solution-Based Approaches Chemical Reviews Arias, A., C., MacKenzie, D., McCulloch, I., Rivnay, J., Salleo, A. 2010; 110: 3
• Microstructural Origin of High-Mobility in High-Performance Poly(thieno-thiophene) Thin Film Transistors Advanced Materials Wang, C., Jimison, L., H., Goris, L., McCulloch, I., Heeney, M., Ziegler, A., Salleo, A. 2010; 22: 697
• Unconvention Face-On Texture and Exceptional In-Plane Order of a High Mobility n-Type Polymer Advanced Materials Rivnay, J., Toney, M., F., Zheng, Y., Kauvar, I., V., Chen, Z., Wagner, V., Salleo, A. 2010; 22: 4359
• Light trapping in thin-film silicon solar cells with submicron surface texture OPTICS EXPRESS Dewan, R., Marinkovic, M., Noriega, R., Phadke, S., Salleo, A., Knipp, D. 2009; 17 (25): 23058-23065

  Abstract

  The influence of nano textured front contacts on the optical wave propagation within microcrystalline thin-film silicon solar cell was investigated. Periodic triangular gratings were integrated in solar cells and the influence of the profile dimensions on the quantum efficiency and the short circuit current was studied. A Finite Difference Time Domain approach was used to rigorously solve the Maxwell's equations in two dimensions. By studying the influence of the period and height of the triangular profile, the design of the structures were optimized to achieve higher short circuit currents and quantum efficiencies. Enhancement of the short circuit current in the blue part of the spectrum is achieved for small triangular periods (P<200 nm), whereas the short circuit current in the red and infrared part of the spectrum is increased for triangular periods (P = 900nm) comparable to the optical wavelength. The influence of the surface texture on the solar cell performance will be discussed.

  View details for Web of Science ID 000272761300083

  View details for PubMedID 20052232

• Large modulation of carrier transport by grain-boundary molecular packing and microstructure in organic thin films NATURE MATERIALS Rivnay, J., Jimison, L. H., Northrup, J. E., Toney, M. F., Noriega, R., Lu, S., Marks, T. J., Facchetti, A., Salleo, A. 2009; 8 (12): 952-958

  Abstract

  Solution-processable organic semiconductors are central to developing viable printed electronics, and performance comparable to that of amorphous silicon has been reported for films grown from soluble semiconductors. However, the seemingly desirable formation of large crystalline domains introduces grain boundaries, resulting in substantial device-to-device performance variations. Indeed, for films where the grain-boundary structure is random, a few unfavourable grain boundaries may dominate device performance. Here we isolate the effects of molecular-level structure at grain boundaries by engineering the microstructure of the high-performance n-type perylenediimide semiconductor PDI8-CN2 and analyse their consequences for charge transport. A combination of advanced X-ray scattering, first-principles computation and transistor characterization applied to PDI8-CN2 films reveals that grain-boundary orientation modulates carrier mobility by approximately two orders of magnitude. For PDI8-CN2 we show that the molecular packing motif (that is, herringbone versus slip-stacked) plays a decisive part in grain-boundary-induced transport anisotropy. The results of this study provide important guidelines for designing device-optimized molecular semiconductors.

  View details for DOI 10.1038/NMAT2570

  View details for Web of Science ID 000272066800014

  View details for PubMedID 19898460

• Ordering of Poly(3-hexylthiophene) Nanocrystallites on the Basis of Substrate Surface Energy ACS NANO Meredig, B., Salleo, A., Gee, R. 2009; 3 (10): 2881-2886

  Abstract

  Molecular dynamics simulations are used to study the influence of functionalized substrates on the orientation of poly(3-hexylthiophene) (P3HT) nanocrystallites, which in turn plays a critical role in P3HT-based transistor performance. The effects of alkyl-trichlorosilane self-assembled monolayer packing density, packing order, and end-group functionality are independently investigated. Across these factors, the potential energy surface presented by the substrate to the P3HT molecules is determined to be the main driver of P3HT ordering. Surprisingly, disordered substrates with a smoothly varying potential energy landscape are found to encourage edge-on P3HT orientation, while highly ordered substrates have undesirable potential energy wells that reduce the edge-on orientation of P3HT because of substrate-side-chain interactions.

  View details for DOI 10.1021/nn800707z

  View details for Web of Science ID 000271106100005

  View details for PubMedID 19746953

• Dual-gate organic thin film transistors as chemical sensors APPLIED PHYSICS LETTERS Park, Y. M., Salleo, A. 2009; 95 (13)

  View details for DOI 10.1063/1.3242372

  View details for Web of Science ID 000270458000079

• Intrinsic and Doped Zinc Oxide Nanowires for Transparent Electrode Fabrication via Low-Temperature Solution Synthesis Goris, L., Noriega, R., Donovan, M., Jokisaari, J., Kusinski, G., Salleo, A. SPRINGER. 2009: 586-595

  View details for DOI 10.1007/s11664-008-0618-x

  View details for Web of Science ID 000263897000019

• Semiconducting Thienothiophene Copolymers: Design, Synthesis, Morphology, and Performance in Thin-Film Organic Transistors ADVANCED MATERIALS McCulloch, I., Heeney, M., Chabinyc, M. L., DeLongchamp, D., Kline, R. J., Coelle, M., Duffy, W., Fischer, D., Gundlach, D., Hamadani, B., Hamilton, R., Richter, L., Salleo, A., Shkunov, M., Sporrowe, D., Tierney, S., Zhong, W. 2009; 21 (10-11): 1091-1109

  View details for DOI 10.1002/adma.200801650

  View details for Web of Science ID 000264662900007

• Large modulation of carrier transport by grain-boundary molecular packing and microsctructure in organic thin films Nature Materials Rivnay, J., Jimison, L., H., Northrup, J., E., Toney, M., F., Noriega, R., Lu, S., Salleo, A. 2009; 8: 952
• Flexible Electronics: Materials and Applications edited by Salleo, A., Wong, W., S. Springer Verlag. 2009
• Light Trapping in Thin Film Silicon Solar Cells with Periodic Pyramid Texture Optics Express Devan, R., Marinkovic, M., Noriega, R., Phadke, S., Salleo, A., Knipp, D. 2009; 17: 23058
• Dual gate organic thin film transistors as chemical sensors Applied Physics Letters Park, Y., M., Salleo, A. 2009; 95: 133307
• Materials and Novel Patterning methods for Flexible Electronics Flexible Electronics: Materials and Applications Wong, W., S., Chabinyc, M., L., Ng, T., N., Salleo, A. edited by Wong, W., W., Salleo, A. Springer Verlag. 2009: 1
• Charge Transport Anisotropy Due to Grain Boundaries in Directionally Crystallized Thin Films of Regio-Regular Poly(3-hexylthiophene) Advanced Materials Jimison, L., H., Toney, M., F., McCulloch, I., Heeney, M., Salleo, A. 2009; 21: 1568
• Correlating the microstructure of thin films of poly[5,5-bis(3-dodecyl-2-thienyl)-2,2-bithiophene] with charge transport: Effect of dielectric surface energy and thermal annealing PHYSICAL REVIEW B Jimison, L. H., Salleo, A., Chabinyc, M. L., Bernstein, D. P., Toney, M. F. 2008; 78 (12)

  View details for DOI 10.1103/PhysRevB.78.125319

  View details for Web of Science ID 000259691500060

• Interfacial effects in thin films of polymeric semiconductors JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B Rivnay, J., Jimison, L. H., Toney, M. F., Preiner, M., Melosh, N. A., Salleo, A. 2008; 26 (4): 1454-1460

  View details for DOI 10.1116/1.2952454

  View details for Web of Science ID 000258494400036

• Connecting electrical and molecular properties of semiconducting polymers for thin-film transistors MRS BULLETIN Chabinyc, M. L., Jimison, L. H., Rivnay, J., Salleo, A. 2008; 33 (7): 683-689

  View details for Web of Science ID 000258014100018

• Connecting Electrical and Molecular Properties of Semiconducting Polymers for Thin Film Transistors MRS Bulletin Chabinyc, M., Jimison, L., H., Rivnay, J., Salleo, A. 2008; 33: 683-689
• Correlating the microstructure of thin films of Poly[5,5’-bis(3-dodecyl-2-thienyl)-2,2’-bithiophene] with charge transport: effect of dielectric surface energy and thermal annealing. Physical Review B Jimison, L., H., Salleo, A., Chabinyc, M., L., Toney, M., F. 2008; 78: 19
• Solution based self-assembly of an be array of polymeric thin-film transistors ADVANCED MATERIALS Salleo, A., Arias, A. C. 2007; 19 (21): 3540-?

  View details for DOI 10.1002/adma.200700445

  View details for Web of Science ID 000250992000019

• Charge transport in polymeric transistors MATERIALS TODAY Salleo, A. 2007; 10 (3): 38-45

  View details for Web of Science ID 000244597300018

• Solution Based Self-Assembly of an Array of Polymeric Thin-Film Transistors Advanced Materials Salleo, A., Arias, A., C. 2007; 19: 3540
• Microstructural effects on the performance of poly(thiophene) thin-film-transistors Salleo, A., Jimison, L., H., Donovan, M., M., Chabinyc, M., L., Toney, M., F. 2006
• Stability of organic transistors Organic Electronics Salleo, A., Chabinyc, M., L. edited by Klauk, H. Wiley-VCH Verlag. 2006: 1
• Jet printing flexible displays Materials Today Street, R., A., Wong, W., S., Ready, S., E., Chabinyc, M., L., Arias, A., C., Limb, S., Salleo, A. 2006; 9: 32
• Reversible and irreversible trapping in poly(thiophene) thin-film-transistors Applied Physics Letters Salleo, A., Endicott, F., Street, R., A. 2005; 86: 263505
• Polymer thin-film-transistor arrays patterned by stamping Advanced Functional Materials Salleo, A., Wong, W., S., Chabinyc, M., L., Paul, K., E., Street, R., A. 2005; 15: 1105
• Printing Methods and Materials for Large-Area Electronic Devices Chabinyc, M., L., Wong, W., S., Arias, A., C., Ready, S., E., Lujan, R., Daniel, J., H., Salleo, A. 2005
• Transport in polycrystalline polymer TFTs Physical Review B Street, R., A., Northrup, J., E., Salleo, A. 2005; 71: 165202
• Kinetics of Bias-stress and Bipolaron formation in regio-regular poly(thiophene) Physical Review B Salleo, A., Street, R., A. 2004; 23 (70): 235324
• Printed polymer transistors and display backplanes Arias, A., C., Ready, S., E., Lujan, R., A., Wong, W., S., Paul, K., E., Chabinyc, M., L., Salleo, A. 2004
• Short-channel effects in regio-regular poly(thiophene) thin-film transistors Chabinyc, M., L., Lu, J., P., Salleo, A., Street, R., A. 2004
• Materials requirements and fabrication of active matrix arrays of organic thin-film-transistors for displays special issue of Chemistry of Materials on Organic Electronics Chabinyc, M., L., Salleo, A. 2004; 23 (16): 4509
• Intrinsic hole mobility and trapping in regio-regular poly(thiophene) Physical Review B Salleo, A., Chen, T., W., Volkel, A., Wu, Y., Liu, P., Ong, B., S. 2004; 7 (70): 115311
• Organic Electronics Flexible Flat Panel Displays Apte, R., B., Ong, B., S., Street, R., A., Salleo, A., Chabinyc, M., L., Arias, A., C. edited by Crawford, G., P. 2004: 1
• Localized state effects in polymer thin-film transistors Journal of Non-Crystalline Solids Street, R., A., Salleo, A., Chabinyc, M., L. 2004; 338-340: 607
• Lamination Method for the Study of Interfaces in Polymeric Thin Film Transistors Journal of the American Chemical Society-Communication Chabinyc, M., L., Salleo, A., Wu, Y., Liu, P., Ong, B., S., Heeney, M. 2004; 43 (126): 13928
• All jet-printed polymer thin film transistor active-matrix backplanes Applied Physics Letters Arias, A., C., Ready, S., E., Lujan, R., Wong, W., S., Paul, K., E., Salleo, A. 2004; 15 (85): 3304
• Light-induced bias stress reversal in polyfluorene thin film transistors Journal of Applied Physics Salleo, A., Street, R., A. 2003; 1 (94): 471
• Printed polymer transistor arrays for displays and imaging Paul, E., Wong, W., S., Chabinyc, M., L., Salleo, A., Ready, S., E., Apte, R., B. 2003
• Bipolaron mechanism for bias-stress effects in organic transistors Physical Review B Street, R., A., Salleo, A., Chabinyc, M., L. 2003; 8 (68): 85316
• Laser driven phase transformations in amorphous silica Nature Materials Salleo, A., Taylor, S., T., Martin, M., C. 2003; 12 (2): 796
• Contact effects in polymer transistors Applied Physics Letters Street, R., A., Salleo, A. 2002; 15 (81): 2887
• Fabrication processes for polymeric organic transistors Salleo, A., Chabinyc, M., L., Paul, K., E., Apte, R., B., Street, R., A., Ong, B., S. 2002
• Continuous-wave InGaN laser diodes on copper and diamond substrates Journal of Materials Research Wong, W., S., Kneissl, M., Treat, D., W., Panero, M., Miyashita, N., Salleo, A. 2002; 4 (17): 1
• Organic Polymeric Thin Film Transistors Fabricated by Selective Dewetting Applied Physics Letters Chabinyc, M., L., Wong, W., S., Salleo, A., Paul, K., E., Street, R., A. 2002; 22 (81): 4260
• High-resolution jet printing for fabrication of a Si:H thin film transistors and arrays Wong, W., S., Ready, S., E., Matusiak, R., White, S., D., Lu, J., P., Ho, J., H., Salleo, A. 2002
• Polymer thin-film transistors with chemically modified dielectric interfaces Applied Physics Letters Salleo, A., Chabinyc, M., L., Street, R., A., Yang, M., S. 2002; 23 (81): 4383
• Energy deposition at front and rear surfaces during picosecond laser interaction with fused silica Applied Physics Letters Salleo, A., Génin, F., Y., Feit, M., D., Teepe, A., M., Sands, T., Russo, R., E. 2001; 19 (78): 2840
• Role of light intensification by cracks in optical breakdown on surfaces Journal of the Optical Society of America A Génin, F., Y., Salleo, A., Pistor, T., V., Chase, L., L. 2001; 10 (18): 2607
• Rear surface laser damage on 355 nm silica optics due to Fresnel diffraction at front surface contamination particles Applied Optics Génin, F., Y., Feit, M., D., Kozlowski, M., R., Rubenchik, A., M., Salleo, A., Yoshiyama, J. 2000; 21 (39): 3654-3663
• Machining of transparent materials using an IR and UV nanosecond pulsed laser Applied Physics A Salleo, A., Sands, T., Génin, F., Y. 2000; 6 (71): 601-608
• Integration of GaN Thin Films with Dissimilar Substrate Materials by Pd-In Metal Bonding and Laser Liftoff Journal of Electronic Materials Wong, W., S., Wengrow, A., B., Cho, Y., Salleo, A., Quitoriano, N., J., Cheung, N., W. 1999; 12 (28): 1409-13
• Crack propagation in fused silica during UV and IR ns-laser illumination. Salleo, A., Chinsio, R., Génin, F., Y. edited by Exarhos et al., G., J. 1999
• Modeling of laser-induced surface cracks in silica at 355 nm Feit, M., D., Campbell, J., Faux, D., Génin, F., Y., Kozlowski, M., R., Rubenchik, A., M., Salleo, A. edited by Exarhos et al., G., J. 1998
• Characterization of nodular and thermal defects in hafnia/silica multilayer coatings using optical, photothermal, and atomic force microscopy Stolz, C., J., Yoshiyama, J., M., Salleo, A., Wu, Z., L., Green, J., Krupka, R. edited by Exarhos et al., G., J. 1998
• Laser-induced damage of fused silica at 355 nm initiated at scratches Salleo, A., Génin, F., Y., Yoshiyama, J., Stolz, C., J., Kozlowski, M., R. edited by Exarhos et al., G., J. 1998
• Pulse-shape and pulse-length scaling of ns pulse laser damage threshold due to rate limiting by thermal conduction. Feit, M., D., Rubenchik, A., M., Salleo, A., Eimerl, D. edited by Exarhos et al., G., J. 1998
• Effects of polishing, etching, cleaving, and water leaching on the UV laser damage of fused silica Yoshiyama, J., Génin, F., Y., Salleo, A., Thomas, I., Kozlowski, M., R., Sheehan, L., M. edited by Exarhos et al., G., J. 1998
• Influence of external mechanical loadings (creep, fatigue) on oxygen diffusion during nickel oxidation. Oxidation of Metals Moulin, G., Arevalo, P., Salleo, A. 1996; 1-2 (45): 153-181
• High temperature reactivity of different forms of carbon at low oxygen fugacity Solid State Ionics, Diffusions & Reactions Gozzi, D., Guzzardi, G., Salleo, A. 1996; 3-4 (83): 177-189