https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/ The latest from Physics » Ultrafast & Terahertz Photonics: Publications (tag [Milot]) 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://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/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://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://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://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 https://iopscience.iop.org/article/10.1088/1361-648X/abfe21 <p><img src="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/intro-figure1.png?maxWidth=300" alt="roadmap" style="margin-right: 10px;" border="0" align="right" /></p> <p><strong>J. Lloyd-Hughes</strong>, P.M. Oppeneer, T. Pereira dos Santos, A. Schleife, S. Meng, M.A. Sentef, M. Ruggenthaler, A. Rubio, I. Radu, M. Murnane, X. Shi, H. Kapteyn, B. Stadtmüller, K.M. Dani, F.H. da Jornada, E. Prinz, M. Aeschlimann, <strong>R.L. Milot</strong>, <strong>M. Burdanova</strong>, J. Boland, T. Cocker and F. Hegmann <br /> J. Phys.: Cond. Matt. <strong><span class="citation_volume">33</span></strong> 353001 (July 2021) <button class="abstractButton" onclick="location.href='https://iopscience.iop.org/article/10.1088/1361-648X/abfe21';">web</button> <button class="abstractButton" onclick="location.href='https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/lloyd-hughes2021.pdf';">pdf</button> <button class="abstractButton" onclick="showHide('lloyd-hughes2021')">abstract</button></p> <div id="lloyd-hughes2021" style="display: none;">In the 60 years since the invention of the laser, the scientific community has developed numerous fields of research based on these bright, coherent light sources, including the areas of imaging, spectroscopy, materials processing and communications. Ultrafast spectroscopy and imaging techniques are at the forefront of research into the light&ndash;matter interaction at the shortest times accessible to experiments, ranging from a few attoseconds to nanoseconds. Light pulses provide a crucial probe of the dynamical motion of charges, spins, and atoms on picosecond, femtosecond, and down to attosecond timescales, none of which are accessible even with the fastest electronic devices. Furthermore, strong light pulses can drive materials into unusual phases, with exotic properties. In this roadmap we describe the current state-of-the-art in experimental and theoretical studies of condensed matter using ultrafast probes. In each contribution, the authors also use their extensive knowledge to highlight challenges and predict future trends.</div> <div align="left"><img src="https://api.elsevier.com/content/abstract/citation-count?doi=10.1088/1361-648X/abfe21&amp;httpAccept=image%2Fjpeg&amp;apiKey=23942728d429d8cd622400c4a7485a23" border="0" /></div> <div class="altmetric-embed" data-badge-popover="right" data-badge-type="2" data-doi="10.1088/1361-648X/abfe21" data-hide-no-mentions="true"></div> THz spectroscopy nanomaterials Milot perovskites Lloyd-Hughes ultrafast review 2021 Mon, 05 Jul 2021 12:02:00 GMT 8a17841a7a5bbe98017a768cc38e6470 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://iopscience.iop.org/article/10.1088/1361-6528/abbce8/meta <p><span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">U. Banin</span></span>, <span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">N. Waiskopf</span></span>, <span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">L. Hammarström</span></span>, <span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">G. Boschloo</span></span>, <span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">M. Freitag</span></span>, <span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">E.M.J. Johansson</span></span>, <span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">J. Sá</span>, </span><span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">H. Tian</span></span>, <span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">M.B. Johnston</span></span>, <span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">L.M. Herz</span></span><span class="reveal-container reveal-plus-icon reveal-enabled"><span class="reveal-content reveal-no-animation">, <strong><span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">R.L. Milot</span></span></strong>, <span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">M.G. Kanatzidis</span>,</span></span></span><span class="reveal-container reveal-plus-icon reveal-enabled"><span class="reveal-content reveal-no-animation"> <span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">W. Ke</span></span>, <span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">I. Spanopoulos</span></span>, <span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">K.L. Kohlstedt,</span></span></span></span><span class="reveal-container reveal-plus-icon reveal-enabled"><span class="reveal-content reveal-no-animation"> <span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">G.C. Schatz</span></span></span></span><span class="reveal-container reveal-plus-icon reveal-enabled"><span class="reveal-content reveal-no-animation">, <span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">N. Lewis</span>, </span></span></span><span class="reveal-container reveal-plus-icon reveal-enabled"><span class="reveal-content reveal-no-animation"><span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">T. Meyer</span></span></span></span><span class="reveal-container reveal-plus-icon reveal-enabled"><span class="reveal-content reveal-no-animation">, <span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">A.J. Nozik</span>, </span></span></span><span class="reveal-container reveal-plus-icon reveal-enabled"><span class="reveal-content reveal-no-animation"><span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">M.C. Beard</span></span></span></span><span class="reveal-container reveal-plus-icon reveal-enabled"><span class="reveal-content reveal-no-animation">, <span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">F. Armstrong</span>, </span></span></span><span class="reveal-container reveal-plus-icon reveal-enabled"><span class="reveal-content reveal-no-animation"><span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">C. F. Megarity</span></span>, <span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">C.A. Schmuttenmaer</span></span></span></span><span class="reveal-container reveal-plus-icon reveal-enabled"><span class="reveal-content reveal-no-animation">, <span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name">V. S. Batista, and G.W. Brudvig</span></span></span></span><span class="reveal-container reveal-plus-icon reveal-enabled"><span class="reveal-content reveal-no-animation"><span itemtype="http://schema.org/Person" itemprop="author" class="nowrap"><span itemprop="name"><br /> </span></span></span></span></p> <p><span class="reveal-container reveal-plus-icon reveal-enabled"><span class="reveal-content reveal-no-animation"><span itemtype="http://schema.org/Person" itemprop="author" class="nowrap">Nanotechnology <strong>32</strong> 042003 (Nov 2020) [<a href="https://iopscience.iop.org/article/10.1088/1361-6528/abbce8/pdf" target="_blank" rel="noopener">pdf</a>] [<a href="https://iopscience.iop.org/article/10.1088/1361-6528/abbce8/meta" target="_blank" rel="noopener">ref</a>]</span></span></span></p> <p><button class="abstractButton" onclick="showHide('banin2020')">Show abstract</button></p> <div id="banin2020" style="display: none;">This roadmap on Nanotechnology for Catalysis and Solar Energy Conversion focuses on the application of nanotechnology in addressing the current challenges of energy conversion: 'high efficiency, stability, safety, and the potential for low-cost/scalable manufacturing' to quote from the contributed article by Nathan Lewis. This roadmap focuses on solar-to-fuel conversion, solar water splitting, solar photovoltaics and bio-catalysis. It includes dye-sensitized solar cells (DSSCs), perovskite solar cells, and organic photovoltaics. Smart engineering of colloidal quantum materials and nanostructured electrodes will improve solar-to-fuel conversion efficiency, as described in the articles by Waiskopf and Banin and Meyer. Semiconductor nanoparticles will also improve solar energy conversion efficiency, as discussed by Boschloo <i>et al</i> in their article on DSSCs. Perovskite solar cells have advanced rapidly in recent years, including new ideas on 2D and 3D hybrid halide perovskites, as described by Spanopoulos <i>et al</i> 'Next generation' solar cells using multiple exciton generation (MEG) from hot carriers, described in the article by Nozik and Beard, could lead to remarkable improvement in photovoltaic efficiency by using quantization effects in semiconductor nanostructures (quantum dots, wires or wells). These challenges will not be met without simultaneous improvement in nanoscale characterization methods. Terahertz spectroscopy, discussed in the article by Milot <i>et al</i> is one example of a method that is overcoming the difficulties associated with nanoscale materials characterization by avoiding electrical contacts to nanoparticles, allowing characterization during device operation, and enabling characterization of a single nanoparticle. Besides experimental advances, computational science is also meeting the challenges of nanomaterials synthesis. The article by Kohlstedt and Schatz discusses the computational frameworks being used to predict structure&ndash;property relationships in materials and devices, including machine learning methods, with an emphasis on organic photovoltaics. The contribution by Megarity and Armstrong presents the 'electrochemical leaf' for improvements in electrochemistry and beyond. In addition, biohybrid approaches can take advantage of efficient and specific enzyme catalysts. These articles present the nanoscience and technology at the forefront of renewable energy development that will have significant benefits to society.</div> THz spectroscopy nanomaterials Milot perovskites 2020 review Mon, 09 Nov 2020 17:46:00 GMT 8a1785d7756ec68b0175ae1e19077848 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