ORCID Profile
0000-0002-7675-0065
Current Organisations
Massachusetts Institute of Technology
,
University of Oxford
,
Imperial College London
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Publisher: Wiley
Date: 06-09-2018
Abstract: Light emission is a critical property that must be maximized and controlled to reach the performance limits in optoelectronic devices such as photovoltaic solar cells and light-emitting diodes. Halide perovskites are an exciting family of materials for these applications owing to uniquely promising attributes that favor strong luminescence in device structures. Herein, the current understanding of the physics of light emission in state-of-the-art metal-halide perovskite devices is presented. Photon generation and management, and how these can be further exploited in device structures, are discussed. Key processes involved in photoluminescence and electroluminescence in devices as well as recent efforts to reduce nonradiative losses in neat films and interfaces are discussed. Finally, pathways toward reaching device efficiency limits and how the unique properties of perovskites provide a tremendous opportunity to significantly disrupt both the power generation and lighting industries are outlined.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9NR09622A
Abstract: This work investigates the formation of APbBr 3 structures (A = CH 3 NH 3 + (MA), Cs + ) in silicon and oxidized silicon nanotubes (SiNTs) with varying inner diameter, as well as the role of the interface in perovskite spectroscopic properties.
Publisher: Springer Science and Business Media LLC
Date: 28-04-2023
DOI: 10.1038/S41467-023-38008-4
Abstract: Detecting low dose rates of X-rays is critical for making safer radiology instruments, but is limited by the absorber materials available. Here, we develop bismuth oxyiodide (BiOI) single crystals into effective X-ray detectors. BiOI features complex lattice dynamics, owing to the ionic character of the lattice and weak van der Waals interactions between layers. Through use of ultrafast spectroscopy, first-principles computations and detailed optical and structural characterisation, we show that photoexcited charge-carriers in BiOI couple to intralayer breathing phonon modes, forming large polarons, thus enabling longer drift lengths for the photoexcited carriers than would be expected if self-trapping occurred. This, combined with the low and stable dark currents and high linear X-ray attenuation coefficients, leads to strong detector performance. High sensitivities reaching 1.1 × 10 3 μC Gy air −1 cm −2 are achieved, and the lowest dose rate directly measured by the detectors was 22 nGy air s −1 . The photophysical principles discussed herein offer new design avenues for novel materials with heavy elements and low-dimensional electronic structures for (opto)electronic applications.
Publisher: American Chemical Society (ACS)
Date: 10-07-2018
DOI: 10.1021/ACS.NANOLETT.8B02190
Abstract: The easily tunable emission of halide perovskite nanocrystals throughout the visible spectrum makes them an extremely promising material for light-emitting applications. Whereas high quantum yields and long-term colloidal stability have already been achieved for nanocrystals emitting in the red and green spectral range, the blue region currently lags behind with low quantum yields, broad emission profiles, and insufficient colloidal stability. In this work, we present a facile synthetic approach for obtaining two-dimensional CsPbBr
Publisher: Elsevier BV
Date: 03-2021
Publisher: Wiley
Date: 18-01-2016
Abstract: Methylammonium lead halide (MAPbX3 ) perovskites exhibit exceptional carrier transport properties. But their commercial deployment as solar absorbers is currently limited by their intrinsic instability in the presence of humidity and their lead content. Guided by our theoretical predictions, we explored the potential of methylammonium bismuth iodide (MBI) as a solar absorber through detailed materials characterization. We synthesized phase-pure MBI by solution and vapor processing. In contrast to MAPbX3, MBI is air stable, forming a surface layer that does not increase the recombination rate. We found that MBI luminesces at room temperature, with the vapor-processed films exhibiting superior photoluminescence (PL) decay times that are promising for photovoltaic applications. The thermodynamic, electronic, and structural features of MBI that are amenable to these properties are also present in other hybrid ternary bismuth halide compounds. Through MBI, we demonstrate a lead-free and stable alternative to MAPbX3 that has a similar electronic structure and nanosecond lifetimes.
Publisher: American Chemical Society (ACS)
Date: 27-06-2022
DOI: 10.1021/JACS.2C02631
Publisher: American Chemical Society (ACS)
Date: 17-06-2021
Publisher: American Chemical Society (ACS)
Date: 17-04-2019
Publisher: American Chemical Society (ACS)
Date: 03-12-2019
Publisher: American Chemical Society (ACS)
Date: 06-08-2015
Publisher: American Chemical Society (ACS)
Date: 22-06-2020
Publisher: Springer Science and Business Media LLC
Date: 24-08-2022
DOI: 10.1038/S41467-022-32669-3
Abstract: I-V-VI 2 ternary chalcogenides are gaining attention as earth-abundant, nontoxic, and air-stable absorbers for photovoltaic applications. However, the semiconductors explored thus far have slowly-rising absorption onsets, and their charge-carrier transport is not well understood yet. Herein, we investigate cation-disordered NaBiS 2 nanocrystals, which have a steep absorption onset, with absorption coefficients reaching 5 cm −1 just above its pseudo-direct bandgap of 1.4 eV. Surprisingly, we also observe an ultrafast (picosecond-time scale) photoconductivity decay and long-lived charge-carrier population persisting for over one microsecond in NaBiS 2 nanocrystals. These unusual features arise because of the localised, non-bonding S p character of the upper valence band, which leads to a high density of electronic states at the band edges, ultrafast localisation of spatially-separated electrons and holes, as well as the slow decay of trapped holes. This work reveals the critical role of cation disorder in these systems on both absorption characteristics and charge-carrier kinetics.
Location: United States of America
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Robert Hoye.