Martyn A. McLachlan

Imperial College London

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James R. Durrant

Imperial College London

Thomas D. Anthopoulos

King Abdullah University of Science and Technology

Chieh‐Ting Lin

National Chung Hsing University

Tian Du

Helmholtz Institute Erlangen-Nürnberg

David W. McComb

The Ohio State University

Thomas J. Macdonald

University College London

Martin Heeney

King Abdullah University of Science and Technology

Claire H. Burgess

Eindhoven University of Technology

Shengda Xu

Shanghai Maritime University

Weidong Xu

University of Cambridge

Cooperative Institutions

Imperial College London

216

Georgia Institute of Technology

135

Royal Society of Chemistry

122

Northwestern University

114

Cambridge Consultants (United Kingdom)

112

University of London

110

Institut de Recherche Interdisciplinaire de Grenoble

109

Pohang University of Science and Technology

CIC nanoGUNE

Transnational Press London

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Vacancy-ordered double-perovskite-based memristors for image processing and pattern recognition

Matter (2024)

Wentong Li Yanyun Ren Tianwei Duan Jing Tang Hao Li

Memristor

Robustness

Neuromorphic engineering

10.1016/j.matt.2024.10.006

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Citations (1)

Interfacial molecular order of conjugated polymer in P3HT:ZnO bilayer photovoltaics and its impact on device performance

Applied Physics Letters (2013)

Sebastian Wood Joseph B. Franklin Paul N. Stavrinou Martyn A. McLachlan Ji‐Seon Kim

Hybrid (organic-oxide) photovoltaic device performance is highly dependent on the nature and quality of the organic-oxide interface. This work investigates the details of interfacial morphology in terms of the molecular order of poly(3-hexylthiophene) (P3HT) at the planar interface with zinc oxide (ZnO) formed by pulsed laser deposition. Resonant Raman spectroscopy is employed as a powerful morphological probe for conjugated polymers to reveal that the interfacial P3HT is disrupted during the deposition process whereas the bulk polymer shows an increase in molecular order. External quantum efficiency measurements of P3HT:ZnO bilayer devices show that this disordered P3HT region is active in photocurrent generation.

Photocurrent

Deposition

10.1063/1.4824847

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Citations (12)

Morphology, microstructure and stability in perovskite photovoltaics (Conference Presentation)

Martyn A. McLachlan

A significant volume of literature exists that describe minor changes in composition and/or microstructure in perovskite solar cells (PSCs) as the driving force for incremental improvements in device performance. Many authors cite crystallinity as a fundamental driver of performance improvements, yet often do so without quantitatively defining crystallinity or, importantly, addressing the important questions behind their observations. Here I will discuss two recent case studies where processing modifications have been investigated as a means of controllably varying active layer crystallinity and describe the impact on device performance. i) We demonstrate the impact of active layer crystallinity on the accumulated charge and open-circuit voltage (Voc) in solar cells based on methylammonium lead triiodide (CH3NH3PbI3,MAPI). We show that MAPI crystallinity can be systematically tailored by modulating the stoichiometry of the precursor mix, where a small excess of methylammonium iodide (MAI) improves crystallinity increasing device Voc by ~200 mV and, in parallel, that the photoluminescence (PL) yield increases 15x, indicative of a suppression of non-radiative recombination pathways. This is coupled with the development of crystallographic texture (110) in the MAPI. In-situ transient optoelectronic measurements of the charge concentration in PSCs under operation suggest that the concentration of trapped charges (either at interfaces or in the bulk) is some 5x lower at matched Voc. We believe these trap states originate in/near the disordered or amorphous areas between MAPI crystallites, resulting at least in part from orientation mismatch between crystalline domains. ii) Secondly, we identify previously unobserved nanoscale defects residing within individual grains of solution processed MAPI thin films. Using scanning transmission electron microscopy (STEM) we identify the defects to be inherently associated with the established solution-processing methodology and introduce a facile processing modification to eliminate such defect formation. Specifically, defect elimination is achieved by co-annealing the as deposited MAPI layer with the electron transport layer PCBM resulting in devices that significantly outperform devices prepared using the established methodology, achieving PCE increases from 13.6 % to 17.7 %. The use of TEM allows us to correlate the performance enhancements to improved intra-grain crystallinity and show that highly coherent crystallographic orientation results within individual grains when processing is modified. Detailed optoelectronic characterization reveals that the improved intra-grain crystallinity drives an improvement of charge collection, a reduction of surface recombination at the MAPI/PCBM interface and a change in the density of local sub-gap states.

10.1117/12.2530213

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Citations (0)

Preparation of large area three-dimensionally ordered macroporous thin films by confined infiltration and crystallisation

Journal of Crystal Growth (2008)

Martyn A. McLachlan Catherine Christine Ann Barron Nigel P. Johnson R.M. De La Rue David W. McComb

Infiltration (HVAC)

Template

10.1016/j.jcrysgro.2008.01.029

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Citations (5)

Electrodeposition of ZnO layers for photovoltaic applications: controlling film thickness and orientation

Journal of Materials Chemistry (2011)

Benoit N. Illy Amy C. Cruickshank S. Schumann Raffaello Da Campo Tim S. Jones

A systematic study of the effect of the zinc oxide (ZnO) electrodeposition parameters (concentration, temperature, potential and pH) on film morphology, thickness, transparency, roughness and crystallographic orientation is presented with the view of producing optimized thin, planar, and continuous ZnO films for photovoltaic applications. Electrochemical measurements of the deposition charge as a function of time are used to understand the mechanism of nucleation and textured growth. Continuous thin films of crystalline ZnO are obtained at temperatures below 100 °C without the need for subsequent annealing. The formation of continuous films is favoured by high concentrations of Zn2+ precursor (> 100 mM), high temperature (> 70 °C) and low potentials (< −1.1 V/AgAgCl). A low bulk solution pH is shown to be a key factor in obtaining thin continuous films and the crystallographic orientation of these films can also be controlled by the deposition parameters. The importance of orientation and thickness control on device performance is shown by using the electrodeposited films as electron extracting interlayers in a model organic photovoltaic system.

Deposition

10.1039/c1jm11225b

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Citations (81)

Front Cover: Influence of Lithium and Lanthanum Treatment on TiO 2 Nanofibers and Their Application in n‐i‐p Solar Cells (ChemElectroChem 14/2019)

ChemElectroChem (2019)

Filip Ambrož Sanjayan Sathasivam Roxy Lee Srinivas Gadipelli Chieh‐Ting Lin

The Front Cover shows a scanning electron microscopy image of lanthanum-treated TiO2 nanofibers rendered to show a three-dimensional representation of the nanostructured solar cell. This work shows that the addition of lithium and lanthanum cations causes minimal substitutional or interstitial doping of TiO2 nanofibers. More information can be found in the Article by F. Ambroz et al. on page 3590 in Issue 14, 2019 (DOI: 10.1002/celc.201900532).

Lanthanum

Front cover

10.1002/celc.201900941

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Copper (I) Selenocyanate (CuSeCN) as a Novel Hole‐Transport Layer for Transistors, Organic Solar Cells, and Light‐Emitting Diodes

Advanced Functional Materials (2018)

Nilushi Wijeyasinghe Leonidas Tsetseris Anna Regoutz Wai‐Yu Sit Zhuping Fei

Abstract The synthesis and characterization of copper (I) selenocyanate (CuSeCN) and its application as a solution‐processable hole‐transport layer (HTL) material in transistors, organic light‐emitting diodes, and solar cells are reported. Density‐functional theory calculations combined with X‐ray photoelectron spectroscopy are used to elucidate the electronic band structure, density of states, and microstructure of CuSeCN. Solution‐processed layers are found to be nanocrystalline and optically transparent (>94%), due to the large bandgap of ≥3.1 eV, with a valence band maximum located at −5.1 eV. Hole‐transport analysis performed using field‐effect measurements confirms the p‐type character of CuSeCN yielding a hole mobility of 0.002 cm 2 V −1 s −1 . When CuSeCN is incorporated as the HTL material in organic light‐emitting diodes and organic solar cells, the resulting devices exhibit comparable or improved performance to control devices based on commercially available poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate as the HTL. This is the first report on the semiconducting character of CuSeCN and it highlights the tremendous potential for further developments in the area of metal pseudohalides.

Nanocrystalline material

10.1002/adfm.201707319

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Citations (28)

Radio Frequency Coplanar ZnO Schottky Nanodiodes Processed from Solution on Plastic Substrates

Small (2016)

J. Edward Semple Stephan Rossbauer Claire H. Burgess Kui Zhao Lethy Krishnan Jagadamma

Coplanar radio frequency Schottky diodes based on solution-processed C60 and ZnO semiconductors are fabricated via adhesion-lithography. The development of a unique asymmetric nanogap electrode architecture results in devices with a high current rectification ratio (103–106), low operating voltage (<3 V), and cut-off frequencies of >400 MHz. Device fabrication is scalable and can be performed at low temperatures even on plastic substrates with very high yield. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

10.1002/smll.201503110

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Citations (54)

Overcoming Nanoscale Inhomogeneities in Thin-Film Perovskites via Exceptional Post-annealing Grain Growth for Enhanced Photodetection

Nano Letters (2022)

Tian Du Filipe Richheimer Kyle Frohna Nicola Gasparini Lokeshwari Mohan

Antisolvent-assisted spin coating has been widely used for fabricating metal halide perovskite films with smooth and compact morphology. However, localized nanoscale inhomogeneities exist in these films owing to rapid crystallization, undermining their overall optoelectronic performance. Here, we show that by relaxing the requirement for film smoothness, outstanding film quality can be obtained simply through a post-annealing grain growth process without passivation agents. The morphological changes, driven by a vaporized methylammonium chloride (MACl)-dimethylformamide (DMF) solution, lead to comprehensive defect elimination. Our nanoscale characterization visualizes the local defective clusters in the as-deposited film and their elimination following treatment, which couples with the observation of emissive grain boundaries and excellent inter- and intragrain optoelectronic uniformity in the polycrystalline film. Overcoming these performance-limiting inhomogeneities results in the enhancement of the photoresponse to low-light (<0.1 mW cm-2) illumination by up to 40-fold, yielding high-performance photodiodes with superior low-light detection.

Photodetection

Passivation

Spin Coating

10.1021/acs.nanolett.1c03839

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Citations (17)

Ultra-thin Al2O3 coatings on BiVO4 photoanodes: Impact on performance and charge carrier dynamics

Catalysis Today (2017)

Andreas Kafizas Xueting Xing Shababa Selim Camilo A. Mesa Yimeng Ma

Bismuth vanadate

Photocurrent

Passivation

Charge carrier

Photoelectrochemistry

10.1016/j.cattod.2017.11.014

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Citations (34)