A5008982684- Organic Electronics and Photovoltaics
- Conducting polymers and applications
- Perovskite Materials and Applications
- Molecular Junctions and Nanostructures
- Luminescence and Fluorescent Materials
- Thin-Film Transistor Technologies
- Organic Light-Emitting Diodes Research
- Fullerene Chemistry and Applications
- Semiconductor materials and interfaces
- Porphyrin and Phthalocyanine Chemistry
- Crystallization and Solubility Studies
- Photochemistry and Electron Transfer Studies
- Chalcogenide Semiconductor Thin Films
- TiO2 Photocatalysis and Solar Cells
- Organic Chemistry Cycloaddition Reactions
- Quantum Dots Synthesis And Properties
- solar cell performance optimization
- Photochromic and Fluorescence Chemistry
- Synthesis and Properties of Aromatic Compounds
- Advanced Photocatalysis Techniques
- Glycosylation and Glycoproteins Research
- Photovoltaic Systems and Sustainability
- Nonlinear Optical Materials Research
- Photovoltaic System Optimization Techniques
- Electrochemical Analysis and Applications
University College London
2016-2025
Transnational Press London
2021
ARC Centre of Excellence for Electromaterials Science
2011-2019
University of Wollongong
2011-2019
Polymer Research Institute
2014-2016
Imperial College London
2008-2013
MacDiarmid Institute for Advanced Materials and Nanotechnology
2005-2010
University of Otago
2003-2010
Merck (United Kingdom)
2010
Georgia Institute of Technology
2010
Abstract The function of organic solar cells is based upon charge photogeneration at donor/acceptor heterojunctions. In this paper, the origin improvement in short circuit current poly(3‐hexylthiophene)/6,6‐phenyl C 61 ‐butyric acid methyl ester (P3HT/PCBM) with thermal annealing examined. Transient absorption spectroscopy employed to demonstrate that results an approximate two‐fold increase yield dissociated charges. enhanced generation correlated a decrease P3HT's ionization potential...
Bimolecular recombination, an important loss mechanism in organic solar cells, has been investigated using transient absorption spectroscopy for poly(3-hexylthiophene):[6,6]-phenyl C61-butyric acid methyl ester (P3HT:PCBM) films and analogues of these components. Data are analyzed as a function blend composition, postdeposition thermal annealing, excitation density. Comparison spectra P3HT:PCBM with analogous employing P3HS PC70BM allows the assignment photoinduced features. These decay...
It is important to accurately measure the charge carrier lifetime, a crucial parameter that influences collection efficiency in organic solar cells. Five transient and small perturbation experimental techniques lifetime are applied device composed of polymer PDTSiTTz blended with fullerene PCBM: time‐resolved extraction (TRCE), absorption spectroscopy (TAS), photoinduced by linearly increasing voltage (photo‐CELIV), photovoltage, electrochemical impedance spectroscopy. The motivation perform...
In this paper we focus upon the role of interfacial energetics in influencing separation charge transfer states into dissociated carriers organic donor/acceptor blend films. particular, undertake transient optical studies films comprising regioregular poly(3-hexylthiophene) (P3HT) blended with a series perylene-3,4:9,10-tetracarboxydiimide (PDI) electron acceptors. For film series, observe close correlation between PDI affinity and efficiency separation. This is discussed context...
The presence of energetically low-lying triplet states is a hallmark organic semiconductors. Even though they present wealth interesting photophysical properties, these optically dark significantly limit optoelectronic device performance. Recent advances in emissive charge-transfer molecules have pioneered routes to reduce the energy gap between triplets and "bright" singlets, allowing thermal population exchange them eliminating significant loss channel devices. In conjugated polymers, this...
Abstract Photovoltaics (PVs) are a critical technology for curbing growing levels of anthropogenic greenhouse gas emissions, and meeting increases in future demand low-carbon electricity. In order to fulfill ambitions net-zero carbon dioxide equivalent (CO 2 eq) emissions worldwide, the global cumulative capacity solar PVs must increase by an magnitude from 0.9 TW p 2021 8.5 2050 according International Renewable Energy Agency, which is considered be highly conservative estimate. 2020, Henry...
Herein we address the factors controlling photocurrent generation in P3HT:PCBM blend films as a function of composition and annealing treatment. Absorption, photoluminescence, transient absorption spectroscopy are used to distinguish role exciton dissociation, charge pair separation, collection. Variations film microstructure with treatment studied using X-ray diffraction. While trend [Muller, et al., Adv. Mater. 2008, 20, 3510] does not follow it closely follows generation. Moreover,...
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication the EditorNEXTUnderstanding Influence of Morphology on Poly(3-hexylselenothiophene):PCBM Solar CellsAmy M. Ballantyne, Toby A. Ferenczi, Mariano Campoy-Quiles, Tracey Clarke, Andrea Maurano, Kien Hon Wong, Weimin Zhang, Natalie Stingelin-Stutzmann, Ji-Seon Kim, Donal D. C. Bradley, James R. Durrant, Iain McCulloch, Martin Heeney, Jenny Nelson*, Steve Tierney, Warren Duffy, Christian Mueller, and Paul SmithView Author...
A new mechanism of charge photogeneration is demonstrated for the first time, based on organic molecular structures. This intermediate band approach, integrated into a dye-sensitised solar cell configuration shown to generate charges upon illumination with low energy photons. Specifically 610 nm photoexcitation Pt porphyrins, through series transfer steps and triplet-triplet annihilation, excites higher absorption onset molecule, which then capable injection TiO2. Transient measurements...
Understanding interfacial charge transfer processes such as trap-mediated recombination and injection into transport layers (CTLs) is crucial for the improvement of perovskite solar cells. Herein, we reveal that chemical binding to CH3NH3PbI3 defect sites an integral part mechanism in both n-i-p p-i-n architectures. Specifically, use a mixture optical X-ray photoelectron spectroscopy show interactions occur via Lewis base between electron-donating moieties on hole surface. We then correlate...
Herein, we present the synthesis and characterization of four conjugated polymers containing a novel chromophore for organic electronics based on an indigoid structure. These exhibit extremely small band gaps ∼1.2 eV, impressive crystallinity, high n-type mobility exceeding 3 cm2 V s–1. The charge carrier can be correlated with remarkably crystallinity along polymer backbone having correlation length in excess 20 nm. Theoretical analysis reveals that have highly rigid nonplanar geometries...
Organic photovoltaics are remarkably close to reaching a landmark power conversion efficiency of 20%. Given the current urgent concerns regarding climate change, research into renewable energy solutions is crucially important. In this perspective article, we highlight several key aspects organic photovoltaics, ranging from fundamental understanding implementation, that need be addressed ensure success promising technology. We cover intriguing ability some acceptors undergo efficient charge...
Two-dimensional transition metal dichalcogenides (2D TMDCs) can be combined with organic semiconductors to form hybrid van der Waals heterostructures.
Abstract Non‐fullerene acceptors have revolutionised organic photovoltaics. However, greater fundamental understanding is needed of the crucial relationships between molecular structure and photophysical mechanisms. Herein, a combination spectroscopic, morphology, device characterization techniques are used to explore these for high‐performing non‐fullerene acceptor, anti‐PDFC. It focuses on transient absorption spectroscopy across multiple timescales ultrafast time‐resolved vibrational...
Charge photogeneration yields and energetics are determined for a low band gap co-polymer, PCPDTBT blended with PC70BM; the increase in charge dithiol is correlated an free energy of separation.
Charge Photogeneration: The correlation between the efficiency of photogeneration dissociated polarons and photocurrent densities for organic solar cells based on polymer:fullerene blend films is investigated. Optical assays polaron yield measured in without electrodes show a remarkably clear with short circuit density quantum complete devices. For studied herein, primary determinant generation dissociation photogenerated charges away from polymer/fullerene interface loss pathway geminate...
In this paper, we use transient absorption spectroscopy to examine the charge photogeneration yields of a series low band gap polythiophenes and polyselenophenes in blend films with 6,6-phenyl C61-butyric acid methyl ester (PCBM). The polymers are selected have approximately matched ionization potentials, allowing us focus upon importance polymer lowest unoccupied molecular orbital (LUMO) level determining efficiency. Data collected as function PCBM composition. A correlation is observed...
Abstract Light induced degradation has been observed in the performance of organic solar cells absence oxygen and a detailed analysis effect this photodegradation on optical electrical features accomplished. This study performed encapsulated photovoltaic blend devices comprised silole‐based donor–acceptor polymer KP115 blended with [6,6]‐phenyl C61‐butyric acid methyl ester (PCBM). Photodegradation induces an almost 20% decrease power conversion efficiency, primarily as result reduction...
The strength of dielectric screening is one the most intriguing yet least studied contributing factors to operation and performance limit organic solar cell devices. Increasing constant semiconducting polymers may close gap between inorganic Here, a 16.7 reported for DPP-based low bandgap polymer DT-PDPP2T-TT 7 its 1:3 blend with [60]PCBM ([6,6]-phenyl-C61-butyric acid methyl ester) using frequency voltage dependent capacitance charge extraction by linearly increasing (CELIV) techniques....
Narrow bandgap conjugated polymers are a heavily studied class of organic semiconductors, but their excited states usually have very short lifetime, limiting scope for applications. One approach to overcome the lifetime is populate long-lived triplet which relaxation ground state forbidden. However, narrow polymer films typically limited few microseconds. Here, we investigated effect film morphology on dynamics in red-emitting based classic benzodithiophene monomer unit with solubilizing...
In this paper, we compare the photophysics and photovoltaic device performance of two indenofluorene based polymers: poly[2,8-(6,6,12,12-tetraoctylindenofluorene)-co-4,7-(2,1,3-benzothiodiazole] (IF8BT) poly[2,8-(6,6,12,12-tetraoctylindenofluorene)-co-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiodiazole] (IF8TBTT) blended with [6,6]-phenyl C61 butyric acid methyl ester (PCBM). Photovoltaic devices made IF8TBTT exhibit greatly superior photocurrent generation efficiency compared to those IF8BT....