https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/ The latest from Physics » Ultrafast & Terahertz Photonics: Publications (tag [ultrafast]) 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://pubs.acs.org/doi/10.1021/acs.jpclett.6c00718 <p><img src="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/currie2026.png?maxWidth=200" alt="Vibrations" style="margin-right: 10px;" border="0" align="right" /></p> <p><strong>A. Currie</strong>, J. Liu, <strong>J.M. Woolley</strong>, and <strong>J. Lloyd-Hughes</strong>, <br />J. Phys. Chem. Lett. <strong>-</strong> - <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> (Apr 2026) <button class="abstractButton" onclick="location.href='https://doi.org/10.1021/acs.jpclett.6c00718';">web</button> <button class="abstractButton" onclick="location.href='https://pubs.acs.org/doi/pdf/10.1021/acs.jpclett.6c00718?ref=article_openPDF';">pdf</button> <button class="abstractButton" onclick="showHide('currie2026')">Show abstract</button></p> <div id="currie2026" style="display: none;">Phonon engineering has improved charge transport in semiconducting organic molecules by introducing high mass side chains, which ameliorate harmful transient localization. The influence of these side chains on thermal energy transfer and dynamic disorder has not been fully explored. In this work, we first use low temperature X-ray diffraction to probe thermally induced structural changes in functionalized acene molecular semiconductors, combined with low temperature IR spectroscopy to track changes to their vibrational energy landscape. Furthermore, time-resolved IR pump&ndash;IR probe spectroscopy is employed to measure IR absorption kinetics associated with the high mass side chains of molecules, revealing intramolecular vibrational energy redistribution pathways. Alkyne groups in the side chains are shown to act as vibrational energy traps, remaining hot for time scales of &gt;2 ns. The results reveal nonequilibrium vibrational pathways associated with side chains that may influence the phonon manifold relevant to dynamic disorder.</div> <div align="left"><img src="https://api.elsevier.com/content/abstract/citation-count?doi=10.1021/acs.jpclett.6c00718&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/acs.jpclett.6c00718" data-hide-no-mentions="true"></div> Lloyd-Hughes ultrafast semiconductors 2026 Tue, 28 Apr 2026 12:36:00 GMT 8ac672c49dcce476019dd4176e591126 https://advanced.onlinelibrary.wiley.com/doi/10.1002/adom.202402011 <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=8ac672c59b07d9a6019b1cce8b5e2b05" alt="image"></div><p><img src="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/Hutchinson2025.png?maxWidth=150" alt="2D-3D" style="margin-right: 10px;" border="0" align="right" /></p> <p class="mb-0"><strong>Jake D. Hutchinson</strong>, Marcin Giza, <strong>Nathaniel P. Gallop</strong>, Benjamin Vella, <strong>Edward Butler-Caddle, Shaoyang Wang, James Lloyd-Hughes,</strong> Pablo Docampo and <strong>Rebecca L Milot</strong></p> <p>Adv. Optical Materials <strong>13</strong> e02011 <span class="cit-pageRange"> </span>(Dec 2025) <button class="abstractButton" onclick="location.href='https://advanced.onlinelibrary.wiley.com/doi/10.1002/adom.202402011';">web</button> <button class="abstractButton" onclick="location.href='https://advanced.onlinelibrary.wiley.com/doi/epdf/10.1002/adom.202402011';">pdf</button> <button class="abstractButton" onclick="showHide('Hutchinson2025')">Show abstract</button></p> <div id="Hutchinson2025" style="display: none;">The incorporation of Ruddlesden&ndash;Popper (RP)/3D perovskite heterostructures into photovoltaic cells has been shown to increase both the efficiency and stability of the devices. Here, a series of methylammonium lead triiodide (MAPbI3) thin films treated with varying 2-phenylethylammonium (PEA) concentrations are investigated with static and ultrafast spectroscopic techniques to reveal the mechanisms of the observed performance benefits. Transient absorption spectroscopy is employed to elucidate the effect of a surface RP layer on the excited state of the MAPbI3 films and reveal that several different RP structures are formed and participate in the charge-carrier dynamics. The passivation effects of PEA are investigated with optical pump&ndash;terahertz probe (OPTP) experiments using a variety of excitation conditions to simultaneously probe the surface and bulk recombination dynamics. Fitting models to the OPTP data for each excitation scheme allows the material parameters that govern the ultrafast dynamics to be quantified. It is found that as the PEA concentration increases, the surface recombination velocity exhibits a monotonic decrease, suggesting the RP layer is effective at passivating surface traps. Furthermore, the bulk monomolecular recombination rate is also found to decrease with the addition of PEA, indicating that the benefits of this passivation approach are not limited to the upper surface of the MAPbI3 films.</div> <div class="altmetric-embed" data-badge-popover="right" data-badge-type="2" data-doi="10.1002/adom.202402011" data-hide-no-mentions="true"></div> THz spectroscopy Milot perovskites Lloyd-Hughes ultrafast highlight 2025 Sun, 14 Dec 2025 12:20:00 GMT 8ac672c59b07d9a6019b1cce8b5e2b05 https://journals.aps.org/prl/abstract/10.1103/mvdf-bdrx <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=8ac672c59ab66a70019ab7d8e2bb0527" alt="image"></div><p><img src="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/keat2025.png?maxWidth=200" alt="Shaping" style="margin-right: 10px;" border="0" align="right" /></p> <p><strong>T.J. Keat</strong>, J. Zhao, <strong>J.M. Woolley</strong>, P. Malakar, G.M. Greetham, X. Wu, J.P. Goss, R.J. Cruddace, C.B. Hartland, M.W. Dale, V.G. Stavros, M.E. Newton and <strong>J. Lloyd-Hughes</strong>, <br />Phys. Rev. Lett. <strong>135</strong> 216902 <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> (Nov 2025) <button class="abstractButton" onclick="location.href='https://doi.org/10.1103/mvdf-bdrx';">web</button> <button class="abstractButton" onclick="location.href='https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/keat2025.pdf';">pdf</button> <button class="abstractButton" onclick="showHide('keat2025')">Show abstract</button></p> <div id="keat2025" style="display: none;">We investigated ultrafast defect-lattice dynamics in diamond using the N_s:H−C⁰ defect, an analog of bond-centered hydrogen in semiconductors. Combining synthesis, ultrafast vibrational spectroscopy, and ab initio calculations, we show that excitation of the defect’s stretch mode leads to the generation of localized phonons and the formation of a hot ground state, where the interatomic potential is transiently modified. Our results reveal unexpected nonequilibrium phonon effects despite diamond’s exceptionally high thermal conductivity, with implications for quantum defect engineering.</div> <div align="left"><img src="https://api.elsevier.com/content/abstract/citation-count?doi=10.1103/mvdf-bdrx&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/mvdf-bdrx" data-hide-no-mentions="true"></div> nanomaterials Lloyd-Hughes ultrafast highlight 2025 Tue, 18 Nov 2025 00:20:00 GMT 8ac672c59ab66a70019ab7d8e2bb0527 https://doi.org/10.1007/s10762-025-01052-w <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=8ac672c796c9abed0196d9ef865d0393" alt="image"></div><p><img src="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/lloyd-hughes2025.png?maxWidth=200" alt="Shaping" style="margin-right: 10px;" border="0" align="right" /></p> <p><strong>J. Lloyd-Hughes</strong>, <strong>N. Chopra</strong>, <strong>J. Deveikis</strong>, R. Pandya and <strong>J. Woolley</strong> <br />J. Infrared mm THz <strong>46</strong> 34 <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 2025) <button class="abstractButton" onclick="location.href='https://doi.org/10.1007/s10762-025-01052-w';">web</button> <button class="abstractButton" onclick="location.href='https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/lloyd-hughes2025.pdf';">pdf</button> <button class="abstractButton" onclick="showHide('lloyd-hughes2025')">Show abstract</button></p> <div id="lloyd-hughes2025" style="display: none;">Electro-optic sampling allows the electric field of THz, mid-infrared and visible light pulses to be measured directly as a function of time, with data analysis often performed in the frequency domain after fast Fourier transform. Here, we review aspects of Fourier theory relevant to the frequency-domain analysis of light pulses recorded in the time domain. We describe a “best practise” approach to using the discrete Fourier transform that ensures consistency with analytical results from the continuous Fourier transform. We summarise a phenomenological time-domain model of THz pulses, based on carrier and envelope waves, and show that it can reproduce a wide variety of experimental single- to multi-cycle THz pulses, with exemplary data from lab-based sources (photoconductive antennae, optical rectification, spintronic emitters) and a THz free-electron laser. A quantitative comparison of the spectral energy density of these distinct sources is enabled by the amplitude-accurate discrete Fourier transform. We describe a method that ensures the accurate calculation of the absolute spectral phase (valid for arbitrary sampling windows in the time domain) and summarise how the carrier-envelope phase, pulse arrival time, and chirp can be obtained from the phase. Our aim with this overview of THz pulse analysis is to highlight algorithms and concepts that are useful to newcomers to time-domain spectroscopy and experts, alike.</div> <div align="left"><img src="https://api.elsevier.com/content/abstract/citation-count?doi=10.1007/s10762-025-01052-w&amp;httpAccept=image%2Fjpeg&amp;apiKey=23942728d429d8cd622400c4a7485a23" border="0" /></div> <div class="altmetric-embed" data-badge-popover="right" data-badge-type="2" data-doi="10.1007/s10762-025-01052-w" data-hide-no-mentions="true"></div> THz components Lloyd-Hughes ultrafast review highlight 2025 Fri, 16 May 2025 16:31:00 GMT 8ac672c796c9abed0196d9ef865d0393 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://iopscience.iop.org/article/10.1088/2053-1591/ad14c2 <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=8ac672c494a5ec430194acf2cc504c4c" alt="image"></div><p><img src="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/Balogun2024.jpg?maxWidth=150" alt="PEA" style="margin-right: 10px;" border="0" align="right" /></p> <p class="mb-0"><strong> <span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">Folusho Helen Balogun</span></span></strong>, <strong><span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">Nathaniel P Gallop</span></span></strong>, <span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">Dumitru Sirbu</span></span>, <strong><span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">Jake D Hutchinson</span></span></strong>, <span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">Nathan Hill</span></span>, <strong><span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">Jack M Woolley</span></span></strong>, <span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">David Walker</span></span>, <span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">Stephen York</span></span>, <span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">Pablo Docampo</span></span> and <strong><span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">Rebecca L Milot</span></span> </strong></p> <p>Mater. Res. Express <strong>11</strong> 025503 <span class="cit-pageRange"> </span>(Feb 2024) <button class="abstractButton" onclick="location.href='https://doi.org/10.1088/2053-1591/ad14c2';">web</button> <button class="abstractButton" onclick="location.href='https://iopscience.iop.org/article/10.1088/2053-1591/ad14c2/pdf';">pdf</button> <button class="abstractButton" onclick="showHide('Balogun2024')">Show abstract</button></p> <div id="Balogun2024" style="display: none;">Layered hybrid perovskites (LPKs) are promising as alternatives or additives to 3D metal halide perovskites for optoelectronic applications including photovoltaic cells, LEDs and lasers due to their increased stability. However, high exciton binding energies in these materials mean that excitons are the majority species under the operating conditions of many devices. Although the efficiency of devices that incorporate LPKs has been increasing, much is still unknown about the interplay of excitons and free charge-carriers in these materials, which is vital information for understanding how optoelectronic properties dictate device efficiency. In this work, we employ optical pump/THz probe spectroscopy (OPTP) and visible transient absorption spectroscopy (TAS) to analyse the optoelectronic properties and charge-carrier dynamics of phenylethylammonium lead iodide (PEA)2PbI4. By combining these techniques, we are able to disentangle the contributions from excitons and free charge-carriers. We observe fast cooling of free charge-carriers and exciton formation on a timescale of ∼400 fs followed by slower bimolecular recombination of residual free charge-carriers with a rate constant k2 ∼ 109 cm3s−1. Excitons recombine via two monomolecular processes with lifetimes t1 ∼ 11 ps and t2 ∼ 83 ps. Furthermore, we detect signatures of exciton&ndash;phonon coupling in the transient absorption kinetic traces. These findings provide new insight into the interplay between free charge-carriers and excitons as well as a possible mechanism to further understand the charge-carrier dynamics in LPKs.</div> <div class="altmetric-embed" data-badge-popover="right" data-badge-type="2" data-doi="10.1088/2053-1591/ad14c21" data-hide-no-mentions="true"></div> THz spectroscopy nanomaterials Milot 2024 perovskites ultrafast Thu, 01 Feb 2024 06:30:00 GMT 8ac672c494a5ec430194acf2cc504c4c https://dx.doi.org/10.1016/j.diamond.2023.110661 <p><img src="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/keat2023.jpg?maxWidth=200" alt="3237" style="margin-right: 10px;" border="0" align="right" /></p> <p><strong>T.J. Keat, D.&thinsp;J.&thinsp;L. Coxon</strong>, R.J. Cruddace, V.&thinsp;G. Stavros, M.&thinsp;E. Newton, and <strong>J. Lloyd-Hughes</strong> <br />Diamond and Related Materials <span class="citation_volume"></span><strong>141<span class="cit-volume"></span></strong><span class="cit-issue"> </span><span class="cit-pageRange">110661</span><strong><span class="citation_volume"></span></strong> (Jan 2024) <button class="abstractButton" onclick="location.href='https://doi.org/10.1016/j.diamond.2023.110661';">web</button> <button class="abstractButton" onclick="location.href='https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/keat2023.pdf';">pdf</button> <button class="abstractButton" onclick="showHide('keat2023')">Show abstract</button></p> <div id="keat2023" style="display: none;">The dynamics of the 3237 cm−1 local vibrational mode in diamond, associated with an unknown defect, was investigated using ultrafast infrared pump-probe spectroscopy. When pumped at 3237 cm−1, a degenerate probe was used to study the ground state's recovery, while a non-degenerate probe tracked excited state absorption at 3029 cm−1, corresponding to the 1 → 2 vibrational state transition. The similar population lifetimes for the ground state recovery and excited state absorption suggests a single population decay pathway, with a lifetime of T₁=2.2+-0.1ps. Perturbed free induction decay signals observed in negative time delays gave the dephasing time of the coherent state between the 0 and 1 vibrational states, and further predicted the 3029 cm−1 transition. Images from FTIR microscopy show that the 3237 cm−1 feature and the 3107 cm−1 absorption line from the N3VH0 defect are not correlated, and our pump-probe study shows the 3237 cm−1 feature does not share a common ground state with the N3VH0 defect, both of which suggest that this local vibrational mode does not originate from the N3VH0 defect. A calibration factor was obtained via a Morse potential model constrained by the observed transition energies, which relates the concentration of the defect producing the 3237 cm−1 feature to its absorption coefficient measured by FTIR spectroscopy. Based on FTIR absorption spectroscopy under uniaxial stress, we further assign a trigonal symmetry character to the defect that gives the 3237 cm−1 feature. The results presented are consistent with the theory that the 3237 cm−1 feature originates from the N4VH defect, the quantification of which allows better tracking of the nitrogen content in diamond.</div> <div align="left"><img src="https://api.elsevier.com/content/abstract/citation-count?doi=10.1016/j.diamond.2023.110661&amp;httpAccept=image%2Fjpeg&amp;apiKey=23942728d429d8cd622400c4a7485a23" border="0" /></div> <div class="altmetric-embed" data-badge-popover="right" data-badge-type="2" data-doi="10.1016/j.diamond.2023.110661" data-hide-no-mentions="true"></div> nanomaterials 2024 Lloyd-Hughes ultrafast Thu, 07 Dec 2023 12:17:00 GMT 8a1785d78c1a55c0018c44361be27146 https://doi.org/10.1021/acsphotonics.3c00918 <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=8a1785d88b8b07d6018b8ef67207070b" alt="image"></div><p><img src="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/Gallop2023.jpeg?maxWidth=150" alt="mDABCO" style="margin-right: 10px;" border="0" align="right" /></p> <p><span class="accordion-tabbed__tab-mobile accordion__closed"><strong>Nathaniel P. Gallop</strong>, Dumitru Sirbu, David Walker, <strong>James Lloyd-Hughes</strong>, Pablo Docampo and <strong>Rebecca L. Milot</strong></span><br />ACS Photonics<span class="citation_volume"><b> 10</b></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">4022</span></span><span class="cit-pageRange"></span><strong><span class="citation_volume"></span><span class="cit-volume"></span></strong><span class="cit-issue"></span><span class="cit-pageRange"> </span>(October 2023) <button class="abstractButton" onclick="location.href='https://doi.org/10.1021/acsphotonics.3c00918';">web</button> <button class="abstractButton" onclick="location.href='https://pubs.acs.org/doi/epdf/10.1021/acsphotonics.3c00918';">pdf</button> <button class="abstractButton" onclick="showHide('Gallop2023')">Show abstract</button></p> <div id="Gallop2023" style="display: none;">We report on the emission of high-intensity pulsed terahertz radiation from the metal-free halide perovskite single crystal methyl-DABCO ammonium iodide (MDNI) under femtosecond illumination. The power and angular dependence of the THz output implicate optical rectification of the 800 nm pump as the mechanism of THz generation. Further characterization finds that, for certain crystal orientations, the angular dependence of THz emission is modulated by phonon resonances attributable to the motion of the methyl-DABCO moiety. At maximum, the THz emission spectrum of MDNI is free from significant phonon resonances, resulting in THz pulses with a temporal width of &lt;900 fs and a peak-to-peak electric field strength of approximately 0.8 kV cm&ndash;1─2 orders of magnitude higher than any other reported halide perovskite emitters. Our results point toward metal-free perovskites as a promising new class of THz emitters that brings to bear many of the advantages enjoyed by other halide perovskite materials. In particular, the broad tunability of optoelectronic properties and ease of fabrication of perovskite materials opens up the possibility of further optimizing the THz emission properties within this material class.</div> <div class="altmetric-embed" data-badge-popover="right" data-badge-type="2" data-doi="10.1021/acsphotonics.3c00918" data-hide-no-mentions="true"></div> THz spectroscopy Milot perovskites Lloyd-Hughes 2023 ultrafast highlight Thu, 02 Nov 2023 07:36:00 GMT 8a1785d88b8b07d6018b8ef67207070b 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://onlinelibrary.wiley.com/doi/full/10.1002/adfm.202305736 <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=8a17841a898c2c3f0189cf9632b94bf6" alt="image"></div><p><img src="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/Hutchinson2023.png?maxWidth=150" alt="CNT" style="margin-right: 10px;" border="0" align="right" /></p> <p><span class="accordion-tabbed__tab-mobile accordion__closed"><strong>Jake D. Hutchinson</strong>, Edoardo Ruggeri, <strong>Jack M. Woolley</strong>, Géraud Delport, Samuel D. Stranks, <strong>Rebecca L. Milot</strong></span><br />Advanced Functional Materials<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">2305736</span><strong><span class="citation_volume"></span><span class="cit-volume"></span></strong><span class="cit-issue">, </span><span class="cit-pageRange"> </span>(August 2023) <button class="abstractButton" onclick="location.href='https://onlinelibrary.wiley.com/doi/full/10.1002/adfm.202305736';">web</button> <button class="abstractButton" onclick="location.href='https://onlinelibrary.wiley.com/doi/epdf/10.1002/adfm.202305736';">pdf</button> <button class="abstractButton" onclick="showHide('hutchinson2023')">Show abstract</button></p> <div id="hutchinson2023" style="display: none;">Mixed 2D/3D perovskite materials are of particular interest to the photovoltaics and light- emitting diode (LED) communities due to their impressive opto-electronic properties alongside improved moisture stability compared to conventional 3D perovskite absorbers. Here, a mixed lead-tin perovskite containing distinct, self-assembled domains of either 3D structures or highly phase-pure Ruddlesden&ndash;Popper 2D structures is studied. The complex energy landscape of the material is revealed with ultrafast optical transient absorption measurements. It is shown that charge transfer between these microscale domains only occurs on nanosecond timescales, consistent with the large size of the domains. Using optical pump-terahertz probe spectroscopy, the effective charge-carrier mobility is shown to be an intermediary between analogous pure 2D and 3D perovskites. Furthermore, detailed analysis of the free carrier recombination dynamics is presented. By combining results from a range of excitation wavelengths within a full dynamic model of the photoexcited carrier population, it is shown that the 2D domains in the film exhibit remarkably similar carrier dynamics to the 3D domains, suggesting that long-range charge-transport should not be impeded by the heterogeneous structure of the material.</div> <div class="altmetric-embed" data-badge-popover="right" data-badge-type="2" data-doi="10.1088/1361-6528/ace1f6" data-hide-no-mentions="true"></div> THz spectroscopy Milot perovskites 2023 ultrafast Mon, 07 Aug 2023 10:41:00 GMT 8a17841a898c2c3f0189cf9632b94bf6