A5029446294- Perovskite Materials and Applications
- Quantum Dots Synthesis And Properties
- Solid-state spectroscopy and crystallography
- Chalcogenide Semiconductor Thin Films
- Conducting polymers and applications
- nanoparticles nucleation surface interactions
- Physics of Superconductivity and Magnetism
- Organic Electronics and Photovoltaics
- Nonlinear Dynamics and Pattern Formation
- Nonlinear Photonic Systems
- Gold and Silver Nanoparticles Synthesis and Applications
- Nonlinear Optical Materials Research
- Adhesion, Friction, and Surface Interactions
- TiO2 Photocatalysis and Solar Cells
- Crystal Structures and Properties
- Optical and Acousto-Optic Technologies
- Silicon Nanostructures and Photoluminescence
- Nanocluster Synthesis and Applications
- Organic and Molecular Conductors Research
- Graphene research and applications
- Molecular Junctions and Nanostructures
- Lignin and Wood Chemistry
- Crystallization and Solubility Studies
- Phase-change materials and chalcogenides
- Thin-Film Transistor Technologies
University of Oxford
2014-2023
Oxfam
2021
Science Oxford
2017
Institute of Spectroscopy
1993-2011
Russian Academy of Sciences
1989-1998
University of Regensburg
1992
Organometal trihalide perovskite based solar cells have exhibited the highest efficiencies to‐date when incorporated into mesostructured composites. However, thin solid films of a absorber should be capable operating at efficiency in simple planar heterojunction configuration. Here, it is shown that film morphology critical issue CH 3 NH PbI 3‐ x Cl cells. The carefully controlled by varying processing conditions, and demonstrated photocurrents are attainable only with surface coverages....
Abstract Single crystals of methylammonium lead trihalide perovskites (MAPbX 3 ; MA=CH NH + , X=Br − or I ) have shown remarkably low trap density and charge transport properties; however, growth such high-quality semiconductors is a time-consuming process. Here we present rapid crystal process to obtain MAPbX single crystals, an order magnitude faster than previous reports. The based on our observation the substantial decrease solubility, in certain solvents, at elevated temperatures. can...
Organic–inorganic metal halide perovskites have recently emerged as a top contender to be used an absorber material in highly efficient, low-cost photovoltaic devices. Solution-processed semiconductors tend high density of defect states and exhibit large degree electronic disorder. Perovskites appear go against this trend, despite relatively little knowledge the impact defects, certified solar-to-electrical power conversion efficiencies up 17.9% been achieved. Here, through treatment crystal...
It has been proposed that organic-inorganic perovskites may provide the ``disruptive'' technology needed to deliver widespread and affordable solar power. To reach this goal, a detailed understanding of their material properties behavior in working devices is needed. The authors present robust model explains charge recombination presence subgap trap states these materials. This study provides concrete predictions regarding most important parameters for improved solar-cell performance perovskites.
Abstract Organic–inorganic perovskites such as CH 3 NH PbI are promising materials for a variety of optoelectronic applications, with certified power conversion efficiencies in solar cells already exceeding 21%. Nevertheless, state-of-the-art films still contain performance-limiting non-radiative recombination sites and exhibit range complex dynamic phenomena under illumination that remain poorly understood. Here we use unique combination confocal photoluminescence (PL) microscopy chemical...
Solution-processed metal halide perovskite semiconductors, such as CH3NH3PbI3, have exhibited remarkable performance in solar cells, despite having non-negligible density of defect states. A likely candidate is vacancies within the crystals, or presence metallic lead, both generated due to imbalanced I/Pb stoichiometry which could evolve during crystallization. Herein, we show that addition hypophosphorous acid (HPA) precursor solution can significantly improve film quality, electronically...
Neutral-colored semitransparent solar cells are commercially desired to integrate into the windows and cladding of buildings automotive applications. Here, we report use morphological control perovskite thin films form planar heterojunction with neutral color comparatively high efficiencies. We take advantage spontaneous dewetting create microstructured arrays "islands", on a length-scale small enough appear continuous eye yet large enable unattenuated transmission light between islands. The...
High-quality perovskite monocrystalline films are successfully grown through cavitation-triggered asymmetric crystallization. These enable a simple cell structure, ITO/CH3NH3PbBr3/Au, with near 100% internal quantum efficiency, promising power conversion efficiencies (PCEs) >5%, and superior stability for prototype cells. Furthermore, the devices using hole-transporter-free structure yield PCEs ≈6.5%, highest among other similar-structured CH3NH3PbBr3 solar cells to date. As service our...
Organic–inorganic metal halide perovskite solar cells have emerged in the past few years to promise highly efficient photovoltaic devices at low costs. Here, temperature‐sensitive core–shell Ag@TiO 2 nanoparticles are successfully incorporated into through a low‐temperature processing route, boosting measured device efficiencies up 16.3%. Experimental evidence is shown and theoretical model developed which predicts that presence of polarizable enhances radiative decay excitons increases...
Abstract Controlling crystal orientations and macroscopic morphology is vital to develop the electronic properties of hybrid perovskites. Here we show that a large-area, orientationally pure crystalline (OPC) methylammonium lead iodide (MAPbI 3 ) perovskite film can be fabricated using thermal-gradient-assisted directional crystallization method relies on sharp liquid-to-solid transition MAPbI from ionic liquid solution. We find OPC films spontaneously form periodic microarrays are...
The exciting intrinsic properties discovered in single crystals of metal halide perovskites still await their translation into optoelectronic devices. poor understanding and control the crystallization process these materials are current bottlenecks retarding shift toward single-crystal-based optoelectronics. Here we theoretically experimentally elucidate role surface tension rapid synthesis perovskite by inverse temperature crystallization. Understanding nucleation growth mechanisms enabled...
The properties of atomically monodisperse noble metal nanoclusters (NCs) are intricately intertwined with their precise molecular formula. vast majority size-specific NC syntheses start from the reduction salt and thiol ligand mixture. Only in gold was it recently shown that ligand-exchange could induce growth NCs one species to another, a process yet unknown reversibility. Here, we present for ligand-exchange-induced silver NCs, biphasic liquid–liquid system, which is particularly interest...
As colloidal quantum dot (CQD) optoelectronic devices continue to improve, interest grows in the scaled-up and automated synthesis of high-quality materials. Unfortunately, all reports record-performance CQD photovoltaics have been based on small-scale batch syntheses. Here we report a strategy for flow reactor PbS CQDs prove that it leads solar cells having performance similar comparable batch-synthesized nanoparticles. Specifically, find that, only when using dual-temperature-stage...
Understanding defect chemistry, particularly ion migration, and its significant effect on the surface's optical electronic properties is one of major challenges impeding development hybrid perovskite-based devices. Here, using both experimental theoretical approaches, we demonstrated that surface layers perovskite crystals may acquire a high concentration positively charged vacancies with complementary negatively halide ions pushed to surface. This charge separation near generates an...
Hybrid organic–inorganic perovskite crystals have recently become one of the most important classes photoactive materials in solar cell and optoelectronic communities. Albeit improvements focused on state-of-the-art technology including various fabrication methods, device architectures, surface passivation, progress is yet to be made understanding actual operational temperature electronic properties performances. Therefore, substantial effect properties, charge separation, recombination...
Metal halide perovskite thin films can be crystallized via a broad range of solution‐based routes. However, the quality final is strongly dependent upon small changes in solution composition and processing parameters. Here, this study demonstrates that fractional substitution PbCl 2 with PbI 3CH 3 NH I:PbCl mixed‐halide starting has profound influence ensuing thin‐film crystallization. The presence precursor induces uniform distribution regular quadrilateral‐shaped CH crystals as‐cast films,...
We analyze nucleation-controlled nanocrystal growth in a solution containing surface-binding molecular ligands, which can also nucleate compact layers on the crystal surfaces. show that, if critical nucleus size for ligands is larger and nucleation barrier lower than those atoms, faster atoms relatively wide facets but much slower, at all, narrow facets. Such competitive of results covering predominantly wider facets, thus excluding them from process, acts as selection mechanism crystals...
Light-induced opening of the fullerene C60 cage due to reaction with excited molecular oxygen (1O2) generated via triplet energy transfer 3O2 has been studied in thin films by differential IR spectroscopy, mass spectroscopy and quantum chemical simulation.
Anisotropy of intermolecular and molecule-substrate interactions holds the key to controlling arrangement fullerenes into 2D self-assembled monolayers (SAMs). The chemical reactivity allows functionalization carbon cages with sulfur-containing groups, thiols thioethers, which facilitates reliable adsorption these molecules on gold substrates. A series structurally related molecules, eight are new fullerene compounds, systematic investigation structural functional parameters defining geometry...
Creating uniform coatings of a solution-cast material is central importance to broad range applications. Here, robust and generic theoretical framework for calculating surface coverage by solid film de-wetting substrate presented. Using experimental data from semiconductor thin films as an example, we calculate wide annealing temperatures thicknesses. The model generally predicts that each value the temperature there thicknesses leading poor coverage. accurately reproduces organometal halide...
A breakthrough in the development of 4D scanning ultrafast electron microscopy is described for real-time and space imaging secondary energy loss carrier diffusion on surface an array nanowires as a model system, providing access to territory that beyond reach either static or any time-resolved laser spectroscopy.
Macromolecules can form regular structures on inert surfaces. We have developed a combined empirical and modeling approach to derive the bonding. From experimental scanning tunneling microscopy images of formed Au(111) by melamine, 3,4,9,10-perylene-tetracarboxylic-dianhydride, 2:3 mixture two, we determine molecular bonding morphologies. Within these morphologies recognizing distinction between cohesive adhesive interactions, simultaneously simulated different using lattice Monte Carlo method.