https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/ The latest from Physics » Ultrafast & Terahertz Photonics: Publications (tag [photoluminescence]) en-GB (C) 2026 University of Warwick Tue, 28 Apr 2026 12:37:45 GMT http://blogs.law.harvard.edu/tech/rss SiteBuilder2, University of Warwick, http://go.warwick.ac.uk/sitebuilder 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 biomedical highlight Lloyd-Hughes MacPherson Milot nanomaterials perovskites photoluminescence review semiconductors THz components THz imaging THz spectroscopy ultrafast Untagged https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.22.024013 <p><img src="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/butler-caddle2024.png?maxWidth=300" alt="Charge transport layers" style="margin-right: 10px;" border="0" align="right" /></p> <p><strong>E. Butler-Caddle,</strong> K.D.G.I. Jayawardena, A. Wijesekara, <strong>R.L. Milot</strong> and <strong>J. Lloyd-Hughes</strong> <br />Phys. Rev. Applied <span class="citation_volume"></span><strong>22<span class="cit-volume"></span></strong><span class="cit-issue"> </span><span class="cit-pageRange">024103</span><strong><span class="citation_volume"></span></strong> (Aug 2024) <button class="abstractButton" onclick="location.href='https://doi.org/10.1103/PhysRevApplied.22.024013';">web</button> <button class="abstractButton" onclick="location.href='https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/butler-caddle2024.pdf';">pdf</button> <button class="abstractButton" onclick="showHide('butler-caddle2024')">Show abstract</button></p> <div id="butler-caddle2024" style="display: none;">In perovskite solar cells, photovoltaic action is created by charge transport layers (CTLs) either side of the light-absorbing metal halide perovskite semiconductor. Hence, the rates for desirable charge extraction and unwanted interfacial recombination at the perovskite-CTL interfaces play a critical role for device efficiency. Here, the electrical properties of perovskite-CTL bilayer heterostructures are obtained using ultrafast terahertz and optical studies of the charge carrier dynamics after pulsed photoexcitation, combined with a physical model of charge carrier transport that includes the prominent Coulombic forces that arise after selective charge extraction into a CTL, and cross-interfacial recombination. The charge extraction velocity at the interface and the ambipolar diffusion coefficient within the perovskite are determined from the experimental decay profiles for heterostructures with three of the highest-performing CTLs, namely C60, PCBM and Spiro-OMeTAD. Definitive targets for the further improvement of devices are deduced: fullerenes deliver fast electron extraction, but suffer from a large rate constant for cross-interface recombination or hole extraction. Conversely, Spiro-OMeTAD exhibits slow hole extraction but does not increase the perovskite’s surface recombination rate, likely contributing to its success in solar cell devices.</div> <div align="left"><img src="https://api.elsevier.com/content/abstract/citation-count?doi=10.1103/PhysRevApplied.22.024013&amp;httpAccept=image%2Fjpeg&amp;apiKey=23942728d429d8cd622400c4a7485a23" border="0" /></div> <div class="altmetric-embed" data-badge-popover="right" data-badge-type="2" data-doi="10.1103/PhysRevApplied.22.024013" data-hide-no-mentions="true"></div> THz spectroscopy photoluminescence Milot 2024 perovskites Lloyd-Hughes ultrafast Tue, 06 Aug 2024 15:12:00 GMT 8a17841a9126f10e0191283fcb962d6c https://pubs.acs.org/doi/10.1021/acs.jpcc.4c03221 <div class="news-thumbnail" style="float: left; margin-right: 10px; margin-bottom: 5px;"><img class="thumbnail" width="100" height="100" src="https://warwick.ac.uk/sitebuilder2/file/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications?sbrPage=%2Ffac%2Fsci%2Fphysics%2Fresearch%2Fcondensedmatt%2Fultrafastphotonics%2Fpublications&newsItem=8a17841b910d330101912470859000c0" alt="image"></div><p><img src="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/Deveikis2024.jpeg?maxWidth=150" alt="ThMAPbI" style="margin-right: 10px;" border="0" align="right" /></p> <p><span class="accordion-tabbed__tab-mobile accordion__closed"><strong>Justas Deveikis</strong>, Marcin Giza, David Walker, Jie Liu, Claire Wilson, <strong>Nathaniel P. Gallop</strong>, Pablo Docampo, <strong>James Lloyd-Hughes</strong> and <strong>Rebecca L. Milot</strong></span><br />J. Phys. Chem. C <span class="citation_volume"><strong>128 </strong></span>13108<span class="cit-issue"></span><span class="cit-issue"><strong><span class="cit-volume"></span></strong><span class="cit-issue">&nbsp;</span></span><span class="cit-pageRange"> </span>(July 2024) <button class="abstractButton" onclick="location.href='https://doi.org/10.1021/acs.jpcc.4c03221';">web</button> <button class="abstractButton" onclick="location.href='deveikis2024.pdf';">pdf</button> <button class="abstractButton" onclick="showHide('Deveikis2024')">Show abstract</button></p> <div id="Deveikis2024" style="display: none;">Improved knowledge of the influence of temperature upon layered perovskites is essential to enable perovskite-based devices to operate over a broad temperature range and to elucidate the impact of structural changes upon the optoelectronic properties. We examined the Ruddlesden&ndash;Popper layered perovskite 2-thiophenemethylammonium lead iodide (ThMA2PbI4) and observed a structural phase transition between a high- and a low-temperature phase at 220&thinsp;K using temperature-dependent X-ray diffraction, UV&ndash;visible absorption, and photoluminescence (PL) spectroscopy. The structural phase transition altered the tilt pattern of the inorganic octahedra layer, modifying the absorption and PL spectra. Further, we found a narrow and intense additional PL peak in the low-temperature phase, which we assigned to radiative emission from a defect-bound exciton state. In both phases we determined the thermal expansion coefficient and found values similar to those of cubic 3D perovskites, i.e., larger than those of typical substrates such as glass. These results demonstrate that the organic spacer plays a critical role in controlling the temperature-dependent structural and optoelectronic properties of layered perovskites and suggests more widely that strain management strategies may be needed to fully utilize layered perovskites in device applications.</div> <div class="altmetric-embed" data-badge-popover="right" data-badge-type="2" data-doi="10.1021/acs.jpcc.4c03221" data-hide-no-mentions="true"></div> photoluminescence Milot 2024 perovskites Lloyd-Hughes highlight Mon, 05 Aug 2024 21:27:00 GMT 8a17841b910d330101912470859000c0 https://dx.doi.org/10.1088/2053-1591/ad18ef <p><img src="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/healy2024.png?maxWidth=200" alt="Shaping" style="margin-right: 10px;" border="0" align="right" /></p> <p>BFM Healy, SL Pain, <strong>J. Lloyd-Hughes</strong>, NE Grant and JD Murphy <br />Materials Research Express<span class="citation_volume"></span><strong><span class="cit-volume"></span></strong><span class="cit-issue"><strong> 11</strong> 015002</span><span class="cit-pageRange"></span><strong><span class="citation_volume"></span></strong> (Jan 2024) <button class="abstractButton" onclick="location.href='https://doi.org/10.1088/2053-1591/ad18ef';">web</button> <button class="abstractButton" onclick="location.href='https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/healy2024.pdf';">pdf</button> <button class="abstractButton" onclick="showHide('healy2024')">Show abstract</button></p> <div id="healy2024" style="display: none;">Monolayer molybdenum disulfide (MoS2) is a promising candidate for inclusion in optoelectronic technologies, owing to its two-dimensional (2D) nature and resultant novel photoluminescence (PL). Chemical vapour deposition (CVD) is an important method for the preparation of large-area films of monolayer MoS2. The PL character of as-prepared monolayer MoS2 must be well understood to facilitate detailed evaluation of any process-induced effects during device fabrication. We comparatively explore the PL emission from four different commercially available CVD-grown MoS2 monolayer films. We characterize the samples via Raman and PL spectroscopy, using both single-spot and mapping techniques, while atomic force microscopy (AFM) is applied to map the surface structure. Via multipeak fitting, we decompose the PL spectra into constituent exciton and trion contributions, enabling an assessment of the quality of the MoS2 monolayers. We find that the PL character varies significantly from sample to sample. We also reveal substantial inhomogeneity of the PL signal across each individual MoS2 film. We attribute the PL variation to non-uniform MoS2 film morphologies that result from the nucleation and coalescence processes during the CVD film development. Understanding the large variability in starting PL behaviour is vital to optimize the optoelectronic properties for MoS2-based devices.</div> <div align="left"><img src="https://api.elsevier.com/content/abstract/citation-count?doi=10.1088/2053-1591/ad18ef&amp;httpAccept=image%2Fjpeg&amp;apiKey=23942728d429d8cd622400c4a7485a23" border="0" /></div> <div class="altmetric-embed" data-badge-popover="right" data-badge-type="2" data-doi="10.1088/2053-1591/ad18ef" data-hide-no-mentions="true"></div> nanomaterials photoluminescence 2024 Lloyd-Hughes Tue, 23 Jan 2024 07:24:00 GMT 8a1785d88ce92c6d018d353541b75f14 https://dx.doi.org/10.1038/s41566-023-01242-9 <p><img src="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/Aobo.png?maxWidth=350" alt="LED" style="margin-right: 10px;" border="0" align="right" /></p> <p>A. Ren, H. Wang, L. Dai, J. Xia, <strong>E. Butler-Caddle</strong>, J.A. Smith, ... S.A. Hindmarsh, A.M. Sanchez, <strong>J. Lloyd-Hughes</strong>, S. J Sweeney, ... and Wei Zhang<br />Nature Photonics<span class="cit-issue"><span class="cit-pageRange"></span></span><span class="cit-pageRange"></span><strong><span class="citation_volume"></span> <span class="cit-volume">17</span></strong><span class="cit-pageRange"></span><strong><span class="cit-volume"></span></strong><span class="cit-issue">, </span><span class="cit-pageRange">798&ndash;805 </span>(July 2023) <button class="abstractButton" onclick="location.href='https://doi.org/10.1038/s41566-023-01242-9';">web</button> <button class="abstractButton" onclick="location.href='https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/ren2023.pdf';">pdf</button> <button class="abstractButton" onclick="showHide('ren2023')">Show abstract</button></p> <div id="ren2023" style="display: none;">Light-emitting diodes (LEDs) are ubiquitous in modern society, with applications spanning from lighting and displays to medical diagnostics and data communications. Metal-halide perovskites are promising materials for LEDs because of their excellent optoelectronic properties and solution processability. Although research has progressed substantially in optimizing their external quantum efficiency, the modulation characteristics of perovskite LEDs remain unclear. Here we report a holistic approach for realizing fast perovskite photonic sources on silicon based on tailoring alkylammonium cations in perovskite systems. We reveal the recombination behaviour of charged species at various carrier density regimes relevant for their modulation performance. By integrating a Fabry&ndash;Pérot microcavity on silicon, we demonstrate perovskite devices with efficient light outcoupling. We achieve device modulation bandwidths of up to 42.6&thinsp;MHz and data rates above 50&thinsp;Mbps, with further analysis suggesting that the bandwidth may exceed gigahertz levels. The principles developed here will support the development of perovskite light sources for next-generation data-communication architectures. The demonstration of solution-processed perovskite emitters on silicon substrates also opens up the possibility of integration with micro-electronics platforms.</div> <div align="left"><img src="https://api.elsevier.com/content/abstract/citation-count?doi=10.1038/s41566-023-01242-9&amp;httpAccept=image%2Fjpeg&amp;apiKey=23942728d429d8cd622400c4a7485a23" border="0" /></div> <div class="altmetric-embed" data-badge-popover="right" data-badge-type="2" data-doi="10.1038/s41566-023-01242-9" data-hide-no-mentions="true"></div> THz spectroscopy nanomaterials photoluminescence perovskites Lloyd-Hughes 2023 ultrafast highlight Sun, 13 Aug 2023 18:37:00 GMT 8a17841a89d4febb0189f030773a4dd7 https://pubs.acs.org/doi/10.1021/acsnano.2c01647 <p><img src="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/hu2022.jpg?maxWidth=300" alt="HgTe" style="margin-right: 10px;" border="0" align="right" /></p> <p><strong>Z. Hu</strong>, B. Breeze, R.J. Kashtiban, J. Sloan and <strong>J. Lloyd-Hughes</strong><br />ACS Nano <span class="citation_volume"></span><span class="cit-issue"></span><span class="cit-issue"><strong><span class="cit-volume"></span></strong><span class="cit-issue"> </span><span class="cit-pageRange"></span></span><span class="cit-pageRange"></span><strong><span class="citation_volume"></span> <span class="cit-volume">16</span></strong><span class="cit-pageRange"> 6789 </span>(Apr 2022) <button class="abstractButton" onclick="location.href='https://doi.org/10.1021/acsnano.2c01647';">web</button> <button class="abstractButton" onclick="location.href='https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/hu2022.pdf';">pdf</button> <button class="abstractButton" onclick="showHide('hu2022')">Show abstract</button></p> <div id="hu2022" style="display: none;">Atomically thin nanowires (NWs) can be synthesized inside single-walled carbon nanotubes (SWCNTs) and feature unique crystal structures. Here we show that HgTe nanowires formed inside small-diameter (&lt;1 nm) SWCNTs can advantageously alter the optical and electronic properties of the SWCNTs. Metallic purification of the filled SWCNTs was achieved by a gel column chromatography method, leading to an efficient extraction of the semiconducting and metallic portions with known chiralities. Electron microscopic imaging revealed that zigzag HgTe chains were the dominant NW geometry in both the semiconducting and metallic species. Equilibrium-state and ultrafast spectroscopy demonstrated that the coupled electron&ndash;phonon system was modified by the encapsulated HgTe NWs, in a way that varied with the chirality. For semiconducting SWCNTs with HgTe NWs, Auger relaxation processes were suppressed, leading to enhanced photoluminescence emission. In contrast, HgTe NWs enhanced the Auger relaxation rate of metallic SWCNTs and created faster phonon relaxation, providing experimental evidence that encapsulated atomic chains can suppress hot carrier effects and therefore boost electronic transport.</div> <div align="left"><img src="https://api.elsevier.com/content/abstract/citation-count?doi=10.1021/acsnano.2c01647&amp;httpAccept=image%2Fjpeg&amp;apiKey=23942728d429d8cd622400c4a7485a23" border="0" /></div> <div class="altmetric-embed" data-badge-popover="right" data-badge-type="2" data-doi="10.1021/acsnano.2c01647" data-hide-no-mentions="true"></div> nanomaterials photoluminescence Lloyd-Hughes 2022 ultrafast Thu, 07 Apr 2022 21:37:00 GMT 8a1785d77faca581018005f5a7594dca https://doi.org/10.1002/aenm.202102776 <p><img src="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/aenm202102776-gra-0001-m.webp" alt="THz round robin" style="margin-right: 10px;" width="300" border="0" align="right" /></p> <p>H. Hempel, T.J. Savenjie, M. Stolterfoht, J. Neu, M. Failla, V.C. Paingad, P. Kužel, E.J. Heilweil, J.A. Spies, M. Schleuning, J. Zhao, D. Friedrich, K. Schwarzburg, L.D.A. Siebbeles, P. Dörflinger, V. Dyakonov, R. Katoh, M.J. Hong, J.G. Labram, <strong>M. Monti, E. Butler-Caddle, J. Lloyd-Hughes</strong>, M.M. Taheri, J.B. Baxter, T.J. Magnanelli, S. Luo, J.M. Cardon, S. Ardo, T. Unold <br />Advanced Energy Materials <span class="citation_volume"></span><strong><span class="cit-volume"></span></strong><span class="cit-issue"> </span><strong><span class="cit-pageRange">2102776</span><span class="citation_volume"></span></strong> (Feb 2022) <button class="abstractButton" onclick="location.href='https://doi.org/10.1002/aenm.202102776';">web</button> <button class="abstractButton" onclick="location.href='https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/hempel2022.pdf';">pdf</button> <button class="abstractButton" onclick="showHide('hempel2022')">Show abstract</button></p> <div id="hempel2022" style="display: none;">Bringing together the expertise from fifteen laboratories the current-voltage characteristics of a solar cell are modeled using contactless terahertz and microwave measurements. To this end, the impact of measurement conditions, alternate interpretations, and experimental inter-laboratory variations are discussed. For a neat (Cs,FA,MA)Pb(I,Br)3 thin film, the implied resistance-free JV-curve and the fill factor losses by its finite mobility are revealed.</div> <div align="left"><img src="https://api.elsevier.com/content/abstract/citation-count?doi=10.1002/aenm.202102776&amp;httpAccept=image%2Fjpeg&amp;apiKey=23942728d429d8cd622400c4a7485a23" border="0" /></div> <div class="altmetric-embed" data-badge-popover="right" data-badge-type="2" data-doi="10.1002/aenm.202102776" data-hide-no-mentions="true"></div> photoluminescence perovskites Lloyd-Hughes 2022 ultrafast Tue, 01 Mar 2022 11:13:00 GMT 8a17841b7f4044ef017f452f53b40dde https://pubs.acs.org/doi/10.1021/acsnano.1c03705 <p><img src="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/kashtiban2021.jpg?maxWidth=300" alt="CsI atomic chains" style="margin-right: 10px;" border="0" align="right" /></p> <p>R.J. Kashtiban, <strong>M.G. Burdanova</strong>, A. Vasylenko, J. Wynn, P.V.C. Medeiros, Q. Ramasse, A.J. Morris, D. Quigley, <strong>J. Lloyd-Hughes</strong> and J. Sloan<br /> ACS Nano <span class="citation_volume"></span><span class="cit-issue"></span><span class="cit-issue"><strong><span class="cit-volume">15</span></strong><span class="cit-issue"> </span><span class="cit-pageRange">13389</span></span><span class="cit-pageRange"></span><strong><span class="citation_volume"></span></strong> (Aug 2021) <button class="abstractButton" onclick="location.href='https://doi.org/10.1021/acsnano.1c03705';">web</button> <button class="abstractButton" onclick="location.href='https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/kashtiban2021.pdf';">pdf</button> <button class="abstractButton" onclick="showHide('kashtiban2021')">Show abstract</button></p> <div id="kashtiban2021" style="display: none;">One-dimensional (1D) atomic chains of CsI were previously reported in double-walled carbon nanotubes with ∼0.8 nm inner diameter. Here, we demonstrate that, while 1D CsI chains form within narrow ∼0.73 nm diameter single-walled carbon nanotubes (SWCNTs), wider SWCNT tubules (∼0.8&ndash;1.1 nm) promote the formation of helical chains of CsI 2 × 1 atoms in cross-section. These CsI helices create complementary oval distortions in encapsulating SWCNTs with highly strained helices formed from strained Cs₂I₂ parallelogram units in narrow tubes to lower strain Cs₂I₂ units in wider tubes. The observed structural changes and charge distribution were analyzed by density-functional theory and Bader analysis. CsI chains also produce conformation-selective changes to the electronic structure and optical properties of the encapsulating tubules. The observed defects are an interesting variation from defects commonly observed in alkali halides as these are normally associated with the Schottky and Frenkel type. The energetics of CsI 2 × 1 helix formation in SWCNTs suggests how these could be controllably formed.</div> <div align="left"><img src="https://api.elsevier.com/content/abstract/citation-count?doi=10.1021/acsnano.1c03705&amp;httpAccept=image%2Fjpeg&amp;apiKey=23942728d429d8cd622400c4a7485a23" border="0" /></div> <div class="altmetric-embed" data-badge-popover="right" data-badge-type="2" data-doi="10.1021/acsnano.1c03705" data-hide-no-mentions="true"></div> nanomaterials photoluminescence Lloyd-Hughes 2021 Tue, 10 Aug 2021 06:47:00 GMT 8a1785d77b065d9b017b2ed0e4051fd3 https://onlinelibrary.wiley.com/doi/10.1002/aenm.202003877 <p><img src="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/balogun2021.jpg?maxWidth=200" alt="Helen review" style="margin-right: 10px;" border="0" align="right" /></p> <p>D. Sirbu, <strong>F. H. Balogun</strong>, <strong>R. L. Milot</strong> and P. Docampo <br /> Advanced Energy Materials <span class="citation_volume"></span><strong><span class="cit-volume"></span></strong><span class="cit-issue"></span><span class="cit-pageRange"></span><strong><span class="citation_volume"></span></strong> (May 2021) <button class="abstractButton" onclick="location.href='https://doi.org/10.1002/aenm.202003877';">web</button> <button class="abstractButton" onclick="location.href='https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/balogun2021.pdf';">pdf</button> <button class="abstractButton" onclick="showHide('balogun2021')">Show abstract</button></p> <div id="balogun2021" style="display: none;">Layered hybrid perovskites (LPKs) have emerged as a viable solution to address perovskite stability concerns and enable their implementation in wide-scale energy harvesting. Yet, although more stable, the performance of devices incorporating LPKs still lags behind that of state-of-the-art, multi-cation perovskite materials. This is typically assigned to their poor charge transport, currently caused by the choice of cations used within the organic layer. On balance, a compromise between efficiency and stability is sought, involving careful control of phase purity and distribution, interfaces and energy/charge transfer processes. Further progress is hindered by the difficulty in identifying the fundamental optoelectronic processes in these materials. Here, the high exciton binding energy of LPKs lead to the formation of multiple photoexcited species, which greatly complicate measurement interpretation. In this light, this review gives an overview of how complementary measurement techniques must be used to separate the contributions from the different species in order to identify device bottlenecks, and become a useful tool to narrow down the limitless list of organic cations. A move away from making compromises to mitigate the impact of poor charge transport is required. The root of the problem must be addressed instead through rational design of the interlayer cations.</div> <div align="left"><img src="https://api.elsevier.com/content/abstract/citation-count?doi=10.1002/aenm.202003877&amp;httpAccept=image%2Fjpeg&amp;apiKey=23942728d429d8cd622400c4a7485a23" border="0" /></div> <div class="altmetric-embed" data-badge-popover="right" data-badge-type="2" data-doi="10.1002/aenm.202003877" data-hide-no-mentions="true"></div> THz spectroscopy nanomaterials photoluminescence Milot perovskites review 2021 Wed, 09 Jun 2021 09:14:00 GMT 8a17841b79d8782b0179f00d29314727 https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/?newsItem=8a17841b76674c940176a3c6f61b624a <p><img src="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/monti2020.png?maxWidth=250" alt="Hot carrier temperatures" style="margin-right: 10px;" border="0" align="right" /></p> <p><strong>M. Monti</strong>, K.D.G.I. Jayawardena, <strong>E. Butler-Caddle, </strong>R.M.I. Bandara, J.M. Woolley, <strong>M. Staniforth</strong>, S.R.P. Silva and<strong> J. Lloyd-Hughes</strong><br /> Phys. Rev. B <strong><span class="citation_volume">102</span></strong> 245204 (Dec 2020) [ <a style="text-decoration: none;" href="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/monti2020.pdf">pdf</a> ] [ <a style="text-decoration: none;" href="https://dx.doi.org/10.1103/PhysRevB.102.245204" target="_blank" rel="noopener">ref </a>]</p> <p><button class="abstractButton" onclick="showHide('monti2020')">Show abstract</button></p> <div id="monti2020" style="display: none;">The electron-phonon interaction controls the intrinsic mobility of charges in metal halide perovskites, and determines the rate at which carriers lose energy. Here, the carrier mobility and cooling dynamics were directly examined using a combination of ultrafast transient absorption spectroscopy and optical pump, THz probe spectroscopy, in perovskites with different lead and tin content, and for a range of carrier densities. Significantly, the carrier mobility in the “hot phonon bottleneck” regime, where the LO phonon bath keeps carriers warm, was found to be similar to the mobility of cold carriers. A model was developed that provides a quantitative description of the experimental carrier cooling dynamics, including electron-phonon coupling, phonon-phonon coupling and the Auger mechanism. In the Pb and Sn alloy the duration of the hot carrier regime was extended as a result of the slower decay of optical phonons. The findings offer an intuitive link between macroscopic properties and the underlying microscopic energy transfer processes, and suggest new routes to control the carrier cooling process in metal halide perovskites to optimize optoelectronic devices.</div> <div align="left"><img src="https://api.elsevier.com/content/abstract/citation-count?doi=10.1103/PhysRevB.102.245204&amp;httpAccept=image%2Fjpeg&amp;apiKey=23942728d429d8cd622400c4a7485a23" border="0" /></div> <div class="altmetric-embed" data-badge-popover="right" data-badge-type="2" data-doi="10.1103/PhysRevB.102.245204" data-hide-no-mentions="true"></div> THz spectroscopy photoluminescence perovskites Lloyd-Hughes 2020 Thu, 24 Dec 2020 10:00:00 GMT 8a17841b76674c940176a3c6f61b624a https://doi.org/10.1039/D0EE00132E <p>M. T. Klug, <strong>R. L. Milot</strong>, J.B. Patel, T. Green, H. C. Sansom, M. D. Farrar, A. J. Ramadan, S. Martani, Z. Wang, B. Wenger, J. M. Ball, L. Langshaw, A. Petrozza, M. B. Johnston, L. M. Herz and H. J. Snaith<br /> Energy &amp; Environmental Science (May 2020) <button class="abstractButton" onclick="location.href='https://doi.org/10.1039/D0EE00132E';">web</button> <button class="abstractButton" onclick="location.href='https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/klug2020.pdf';">pdf</button> <button class="abstractButton" onclick="showHide('klug2020')">Show abstract</button></p> <p><img src="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/klug2020.gif" alt="Klug 2020" style="margin-right: 5px; margin-left: 5px;" width="222" border="0" align="right" /></p> <div id="klug2020" style="display: none;">Current designs for all-perovskite multi-junction solar cells require mixed-metal Pb&ndash;Sn compositions to achieve narrower band gaps than are possible with their neat Pb counterparts. The lower band gap range achievable with mixed-metal Pb&ndash;Sn perovskites also encompasses the 1.3 to 1.4 eV range that is theoretically ideal for maximising the efficiency of single-junction devices. Here we examine the optoelectronic quality and photovoltaic performance of the ((HC(NH<small>₂</small>)<small>₂</small>)<small>_0.83</small>Cs<small>_0.17</small>)(Pb<small>_{1−<em>y</em>}</small>Sn<small>_<em>y</em></small>)I<small>₃</small> family of perovskite materials across the full range of achievable band gaps by substituting between 0.001% and 70% of the Pb content with Sn. We reveal that a compositional range of “defectiveness” exists when Sn comprises between 0.5% and 20% of the metal content, but that the optoelectronic quality is restored for Sn content between 30&ndash;50%. When only 1% of Pb content is replaced by Sn, we find that photoconductivity, photoluminescence lifetime, and photoluminescence quantum efficiency are reduced by at least an order of magnitude, which reveals that a small concentration of Sn incorporation produces trap sites that promote non-radiative recombination in the material and limit photovoltaic performance. While these observations suggest that band gaps between 1.35 and 1.5 eV are unlikely to be useful for optoelectronic applications without countermeasures to improve material quality, highly efficient narrower band gap absorber materials are possible at or below 1.33 eV. Through optimising single-junction photovoltaic devices with Sn compositions of 30% and 50%, we respectively demonstrate a 17.6% efficient solar cell with an ideal single-junction band gap of 1.33 eV and an 18.1% efficient low band gap device suitable for the bottom absorber in all-perovskite multi-junction cells.</div> <div align="left"><img src="https://api.elsevier.com/content/abstract/citation-count?doi=10.1039/D0EE00132E&amp;httpAccept=image%2Fjpeg&amp;apiKey=23942728d429d8cd622400c4a7485a23" border="0" /></div> <div class="altmetric-embed" data-badge-popover="right" data-badge-type="2" data-doi="10.1039/D0EE00132E" data-hide-no-mentions="true"><br /> <br /> </div> THz spectroscopy photoluminescence Milot perovskites 2020 Fri, 01 May 2020 12:00:00 GMT 8a1785d774f8c62a017502f1a46a4f97