A5021077413- Organic Electronics and Photovoltaics
- Conducting polymers and applications
- Fullerene Chemistry and Applications
- Organic Light-Emitting Diodes Research
- Semiconductor materials and interfaces
- Perovskite Materials and Applications
- Thin-Film Transistor Technologies
- Spectroscopy and Quantum Chemical Studies
- Molecular Junctions and Nanostructures
- Photoreceptor and optogenetics research
- Graphene research and applications
- Diamond and Carbon-based Materials Research
- Advanced Sensor and Energy Harvesting Materials
- Carbon Nanotubes in Composites
- Near-Field Optical Microscopy
- solar cell performance optimization
- Quantum Dots Synthesis And Properties
- Advanced Chemical Physics Studies
- Zeolite Catalysis and Synthesis
- Electrochemical sensors and biosensors
- Semiconductor materials and devices
- Ferroelectric and Piezoelectric Materials
- Organic and Molecular Conductors Research
- Photovoltaic System Optimization Techniques
- Architecture and Computational Design
Imperial College London
2014-2024
Transnational Press London
2018
University of Wollongong
2014
Technical University of Denmark
2014
Fujitsu (United Kingdom)
2005
Ben-Gurion University of the Negev
2001-2003
Herein, we report experimental studies of electron and hole transport in thin films [6,6]-phenyl C61 butyric acid methyl ester (PCBM) blends poly[2-methoxy-5-(3′,7′-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) with PCBM. The low-field mobility pristine MDMO-PPV is the order 10–7 cm2 V–1 s–1, agreement previous studies, whereas PCBM was found by current-density–voltage (J–V) measurements to be 10–2 which about one magnitude greater than previously reported. Adding blend increases both...
We report on the temperature dependence of various photovoltaic device parameters solar cells, fabricated from interpenetrating networks conjugated polymers with fullerenes, in wide range their possible operating conditions (25–60 °C). The open-circuit voltage was found to decrease linearly increasing temperature. For short-circuit current, we observed a monotonic increase temperature, followed by saturation region. rate this (coupled corresponding for fill factor) overtake voltage,...
Environmental stability is a common challenge for the commercialisation of low cost, encapsulation-free organic opto-electronic devices.
Abstract The use of fullerenes with two or more adducts as acceptors has been recently shown to enhance the performance bulk‐heterojunction solar cells using poly(3‐hexylthiophene) (P3HT) donor. enhancement is caused by a substantial increase in open‐circuit voltage due rise fullerene lowest unoccupied molecular orbital (LUMO) level when going from monoadducts multiadducts. While obtained many different polymers, most polymers other than P3HT show substantially reduced photocurrent blended...
Detailed studies of hole mobility in the electroluminescent conjugated polymer poly($9,{9}^{\ensuremath{'}}$-dioctylfluorene) by time-of-flight technique are reported. The is studied a number samples over wide range temperatures and electric field strengths. Significant sample-to-sample variations observed both character transport as-spun films different thicknesses. Hole found to improve irreversibly as result thermal annealing at elevated temperatures. Analysis experimental results carried...
All-organic-based photovoltaic solar cells have attracted considerable attention because of their low-cost processing and short energy payback time. In such systems the primary dissociation an optical excitation into a pair photocarriers has been recently shown to be extremely rapid efficient, but physical reason for this remains unclear. Here, two-dimensional photocurrent spectroscopy, novel non-linear is used probe ultrafast coherent decay photoexcitations charge-producing states in...
Monte Carlo algorithms are used to simulate the morphologies adopted by polymer chains in a polymer-blend film limits where mutually attractive (homophilic regime) and repulsive (heterophilic then drift transport of charges through chains. In homophilic regime, aggregate into tangled domains resulting relatively high percolation threshold, density configurational trap states, slow, dispersive charge transport. heterophilic regime at same volume fraction, self-organize lacework pattern low...
Conjugated oligomers with various ratios of cyclopentadithiophene (CPDT) to benzothiadiazole (BT) repeating units are reported. These can be polymerised high molecular weight polymers (Mn > 100k) by oxidative polymerisation using iron(III)chloride. The electronic properties these materials were examined cyclic voltammetry and UV-vis spectroscopy the results compared those calculated density functional theory (DFT). Polymers optimum CPDT : BT (2 1) show hole mobilities in excess 10−2 cm2 V−1...
We analyze the voltage losses at open circuit in solution-processed, small-molecule:fullerene blend solar cells, using electroluminescence and external quantum efficiency measurements reciprocity relationship between light absorption emission. For cells made from oligo-thienylenevinylene-based donors phenyl-C71 butyric acid methyl ester (PC71BM), we find that loss due to finite breadth of edge is remarkably small, less than 0.01 eV best cases, while nonradiative recombination reaches 0.29...
High power conversion efficiency (PCE) inverted organic photovoltaics (OPVs) usually use thermally evaporated MoO3 as a hole transporting layer (HTL). Despite the high PCE values reported, stability investigations are still limited and exact degradation mechanisms of OPVs using HTL remain unclear under different environmental stress factors. In this study, we monitor accelerated lifetime performance ISOS-D-2 protocol (heat conditions 65 °C) nonencapsulated based on thiophene-based active...
Exchanging hydrophobic alkyl-based side chains to hydrophilic glycol-based is a widely adopted method for improving mixed-transport device performance, despite the impact on solid-state packing and polymer-electrolyte interactions being poorly understood. Presented here molecular dynamics (MD) force field modeling alkoxylated glycolated polythiophenes. The validated against known motifs their monomer crystals. MD simulations, coupled with X-ray diffraction (XRD), show that polythiophenes...
Semiconducting conjugated polymers bearing glycol side chains can simultaneously transport both electronic and ionic charges with high charge mobilities, making them ideal electrode materials for a range of bioelectronic devices. However, heavily glycolated polymer films have been observed to swell irreversibly when subjected an electrochemical bias in aqueous electrolyte. The excessive swelling lead the degradation their microstructure, subsequently reduced device performance. An effective...
The effect of a magnetic field on the photocurrent generated by bulk heterojunction solar cell made from poly-3-hexylthiophene (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM) is investigated. At operating voltage, increases in ∼9% can be obtained at fields less than 100 mT. This increase attributed to an rate intersystem crossing, between singlet triplet states, leading higher net efficiency exciton dissociation. Close open-circuit more two orders magnitude could under applied field.
Donor–acceptor–donors containing 4<italic>H</italic>-1,2,6-thiadiazinone are presented and used in organic solar cells.
Novel optoelectronic devices rely on complex nanomaterial systems where the nanoscale morphology and local chemical composition are critical to performance. However, lack of analytical techniques that can directly probe these structure–property relationships at presents a major obstacle device development. In this work, we present novel method for non-destructive, simultaneous mapping morphology, photoelectrical properties with <20 nm spatial resolution by combining plasmonic optical signal...
The microstructure of blend films conjugated polymer and fullerene, especially the degree mixing crystallization, impacts performance organic photovoltaic devices considerably. Mixing crystallization affect device in different ways. These phenomena are not easy to screen using traditional methods such as imaging. In this paper, amorphous regiorandom poly(3‐hexylthiophene) is blended with potentially crystalline fullerene [6,6]‐phenyl‐C 61 ‐butyric acid methyl ester PCBM bis‐adduct. First,...
The performance of photovoltaic devices based on blends conjugated polymers with nonfullerene acceptors depends the phase behavior and microstructure binary, which in turn chemical structures molecular components blend composition. We investigate correlation between structure, composition, behavior, device a model system consisting semicrystalline poly-3-hexylthiophene (P3HT) as donor polymer three acceptors, two (O-IDTBR/EH-IDTBR) have planar core different side chains one (O-IDFBR) has...
We report on the hole transport characteristics, as measured by time of flight, a family symmetrically substituted dialkoxy poly($p$-phenylenevinylene) polymers with different side-chain length. As length is decreased, magnitude mobility ${\ensuremath{\mu}}_{h}$ increases while field dependence becomes more positive and temperature stronger. For shortest derivative studied, exceeds ${10}^{\ensuremath{-}4}\text{ }{\text{cm}}^{2}\text{ }{\text{V}}^{\ensuremath{-}1}\text{...