A5019768547- Organic Electronics and Photovoltaics
- Conducting polymers and applications
- Organic Light-Emitting Diodes Research
- Thin-Film Transistor Technologies
- Photonic and Optical Devices
- Semiconductor materials and devices
- Photorefractive and Nonlinear Optics
- Perovskite Materials and Applications
- Advanced Fiber Laser Technologies
- Advanced Memory and Neural Computing
- Nonlinear Optical Materials Studies
- Analytical Chemistry and Sensors
- Luminescence and Fluorescent Materials
- Advanced Sensor and Energy Harvesting Materials
- Photonic Crystals and Applications
- Nonlinear Optical Materials Research
- Advanced Optical Imaging Technologies
- Molecular Junctions and Nanostructures
- Plasmonic and Surface Plasmon Research
- Green IT and Sustainability
- Optical Coatings and Gratings
- ZnO doping and properties
- Gold and Silver Nanoparticles Synthesis and Applications
- Tactile and Sensory Interactions
- Liquid Crystal Research Advancements
Northeastern University
2022-2025
Georgia Institute of Technology
2015-2024
AID Atlanta
2016-2021
University of Arizona
2000-2004
Optical Sciences (United States)
2001-2004
Center for Scientific Research and Higher Education at Ensenada
1999
Université de franche-comté
1985-1988
Centre National de la Recherche Scientifique
1988
Organic and printed electronics technologies require conductors with a work function that is sufficiently low to facilitate the transport of electrons in out various optoelectronic devices. We show surface modifiers based on polymers containing simple aliphatic amine groups substantially reduce including metals, transparent conductive metal oxides, conducting polymers, graphene. The reduction arises from physisorption neutral polymer, which turns modified into efficient electron-selective...
Solar energy is potentially the largest source of renewable at our disposal, but significant advances are required to make photovoltaic technologies economically viable and, from a life-cycle perspective, environmentally friendly and consequently scalable. Cellulose nanomaterials emerging high-value nanoparticles extracted plants that abundant, sustainable. Here, we report on first demonstration efficient polymer solar cells fabricated optically transparent cellulose nanocrystal (CNC)...
Low-noise organic photodetectors Although the high performance and low cost of visible light silicon suffice for most applications, their small size rigid nature are not optimal applications such as wearable sensors. Organic can be flexible large in area but often noisy. Fuentes-Hernandez et al. found that optimized choices semiconductor electrode materials improve diode characteristics enable detect levels with noise. Science , this issue p. 698
We report on inverted polymer tandem solar cells wherein the conducting poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), modified at one interface with ethoxylated polyethylenimine (PEIE), acts as an efficient charge recombination layer. This layer shows very low optical absorption, high electrical conductivity, and a large work function contrast of 1.3 eV between its top bottom interfaces. Its use yields in which open-circuit voltage is sum that individual cells. The...
Top-gate organic field-effect transistors are demonstrated using a bilayer gate dielectric to propose new compensation mechanism which leads high operational stability. Neither changes in mobility nor threshold voltage observed after 20 000 cycles of the transfer characteristics or 24 hours under constant direct-current bias stress. We also demonstrate that these OFETs air stable up 210 days. Over past several years, great progress has been made development (OFETs). Prototypes electronic...
We report on low-voltage, high-performance amorphous indium gallium zinc oxide n-channel thin-film transistors fabricated using 100-nm-thick Al2O3 grown by atomic layer deposition as the gate dielectric layer. The shows very small current densities and has a capacitance density of 81±1 nF/cm2. Due to contact resistance, with channel lengths ranging from 100 μm down 5 yield channel-independent, field-effect mobility 8±1 cm2/V s, subthreshold slopes 0.1±0.01 V/decade, low threshold voltages...
We report on indium tin oxide (ITO)-free and metal-free semitransparent organic solar cells with a high-conductivity poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) (PH1000) as both the bottom top electrodes. The PH1000 film showed conductivity of 680±50 S/cm. A ZnO layer was used an interlayer to produce electron-selective electrode. devices structure glass/PH1000/ZnO/poly(3-hexylthiophene):phenyl-C61-butyric acid methyl ester/PEDOT:PSS (CPP 105 D)/PH1000 exhibited...
Organometal halide perovskites have shown excellent optoelectronic properties and been used to demonstrate a variety of semiconductor devices. Colorful solar cells are desirable for photovoltaic integration in buildings other aesthetically appealing applications. However, the realization colorful perovskite is challenging because their broad large absorption coefficient that commonly leads with dark-brown colors. Herein, first time, we report simple efficient strategy achieve by using...
Organic thin-film transistors exhibit an unprecedented level of reliability, bringing them closer to commercialization.
We report on a systematic study of solvent and polymer matrix effects the phase segregation behavior 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-pentacene) blends incorporated into two different amorphous matrices, poly (α-methyl styrene) (triarylamine), using solvents, chlorobenzene tetralin. Optical microscopy, X-ray diffraction analyses, optical absorption measurements are used to evaluate film morphology, crystallinity, density, respectively. These analyses correlated with extent...
We report on reversible changes of the work function (WF) values indium-tin-oxide (ITO) under prolonged ultraviolet (UV) and air exposure. The WF ITO is reduced from 4.7 eV to 4.2 by photon absorption in UV illumination or an mass 1.5 solar simulator (100 mW cm(-2)). Air oxygen exposure found increase (UV-exposed) a value 4.6 eV. These ITO's lead variations performance organic photovoltaic devices where acts primarily as electron collecting hole electrode. can be reflected disappearance (or...
We report on semitransparent air-processed all-plastic solar cells, fabricated from vacuum-free processes, comprising two polymer electrodes, a polymeric work-function modification layer and polymer:fullerene photoactive layer. The active the top PEDOT:PSS electrode were prepared by sequential film-transfer lamination polyethylenimine-modified bottom electrodes. transferring of films offers ease patterning misalignment defects in different layers resulting additive film transfer process...
We report on the reduction of contact resistance in solution-processed TIPS-pentacene (6,13-bis(triisopropylsilylethynyl)pentacene) and PTAA (poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]) top-gate bottom-contact organic field-effect transistors (OFETs) by using different contact-modification strategies. The study compares values devices that comprise Au source/drain electrodes either treated with 2,3,4,5,6-pentafluorothiophenol (PFBT), or modified an evaporated thin layer metal–organic...
N-Heterocyclic carbenes (NHCs) bind strongly to gold and other metals. This work experimentally probes the effect of NHCs on function (WF) for first time, theoretically analyzes origin this effect, examines effectiveness NHC-modified as an electron-injecting electrode. UV photoelectron spectroscopy shows WF planar is reduced by nearly 2 eV values 3.3–3.5 eV. seen with various heterocyclic cores, either small or large N,N′-substituents. DFT calculations indicate reduction results from both...
We report on the photovoltaic properties of inverted polymer solar cells where transparent electron-collecting electrode is formed by a ZnO-modified indium−tin oxide (ITO) electrode. The ZnO layers were deposited atomic layer deposition (ALD) with varying thicknesses from 0.1 to 100 nm. work function, surface roughness, and morphology ITO/ZnO found be independent thickness. However, device performance was strongly dependent critical thickness, around 10 Below thickness degraded because...
We report on the properties of inverted polymer solar cells using an ultrathin Al2O3 buffer layer indium tin oxide (ITO). The layer, deposited by atomic deposition method, was found to reduce work function ITO and turns into electron-collecting electrode. current density–voltage characteristics unexposed devices showed s-shape kink. kink eliminated upon exposure ultraviolet (UV) illumination. Inverted based P3HT:PC60BM yielded a fill factor 0.64 power conversion efficiency about 2.8%...
The electron deficiency and trans-planar conformation of bithiazole is potentially beneficial for the electron-transport performance organic semiconductors. However, incorporation into polymers through a facile synthetic strategy remains challenge. Herein, 2,2′-bithiazole was synthesized in one step copolymerized with dithienyldiketopyrrolopyrrole to afford poly(dithienyldiketopyrrolopyrrole-bithiazole), PDBTz. PDBTz exhibited mobility reaching 0.3 cm2 V–1 s–1 field-effect transistor (OFET)...
Poly(3‐hexylthiophene) (P3HT) is p‐doped by the new soluble dopant molybdenum tris[1‐(methoxycarbonyl)‐2‐(trifluoromethyl)‐ethane‐1,2‐dithiolene] and investigated via photoemission spectroscopy transport measurements. Soft‐contact transfer lamination of thin layers doped P3HT on undoped polymer used to create spatially‐confined regions, which serve as hole‐injection contacts diodes. This strategy then efficient hole‐collecting solution‐processed inverted solar cells.
Flexible all-plastic multijunction solar cells with high photovoltage have been demonstrated <italic>via</italic> optimization of the charge-recombination layer and shown to power portable electronics.
Stretchable optoelectronics made of elastomeric semiconductors could enable the integration intelligent systems with soft materials, such as those biological world. Organic and photodiodes have been engineered to be elastomeric; however, for photodetector applications, it remains a challenge identify an bulk heterojunction (e-BHJ) photoactive layer that combines low Young’s modulus high strain at break yields organic electronic noise values performance. Here, blend elastomer, donor-like...
A new solution-processable small-molecule containing electron-poor naphthalene diimide and tetrazine moieties has been synthesized. The optimized spin-coated n-channel OFETs on glass substrate shows electron mobility value up to 0.15 cm2 V−1 s−1. Inkjet-printed are fabricated in ambient atmosphere flexible plastic substrates, which exhibits an 0.17 s−1and also excellent environmental operational stability. Detailed facts of importance specialist readers published as "Supporting Information"....