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Gillespie, Sarah C. (author), van der Laan, Marco (author), Poonia, D. (author), Maiti, Sourav (author), Kinge, S.S. (author), Siebbeles, L.D.A. (author), Schall, Peter (author)Heterostructures (HSs) based on two-dimensional transition metal dichalcogenides (TMDCs) are highly intriguing materials because of the layers’ pronounced excitonic properties and their nontrivial contributions to the HS. These HSs exhibit unique properties that are not observed in either of the constituent components in isolation. Interlayer...review 2024
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Weerdenburg, S. (author), Singh, N. (author), van der Laan, Marco (author), Kinge, Sachin (author), Schall, Peter (author), Siebbeles, L.D.A. (author)We present a theoretical model to compute the efficiency of the generation of two or more electron-hole pairs in a semiconductor by the absorption of one photon via the process of carrier multiplication (CM). The photogeneration quantum yield of electron-hole pairs is calculated from the number of possible CM decay pathways of the electron...journal article 2024
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Gabbett, Cian (author), Kelly, Adam G. (author), Coleman, Emmet (author), Doolan, Luke (author), Carey, Tian (author), Synnatschke, Kevin (author), Ghosh, G. (author), Siebbeles, L.D.A. (author), Coleman, Jonathan N. (author)Networks of nanowires, nanotubes, and nanosheets are important for many applications in printed electronics. However, the network conductivity and mobility are usually limited by the resistance between the particles, often referred to as the junction resistance. Minimising the junction resistance has proven to be challenging, partly because it...journal article 2024
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van der Laan, M. (author), Heemskerk, Edwin (author), Kienhuis, Floris (author), Poonia, D. (author), Kinge, S.S. (author), Dang, Minh Triet (author), Dinh, Van An (author), Siebbeles, L.D.A. (author), Isaeva, Anna (author), Schall, Peter (author)Rhenium disulfide, a member of the transition metal dichalcogenide family of semiconducting materials, is unique among 2D van der Waals materials due to its anisotropy and, albeit weak, interlayer interactions, confining excitons within single atomic layers and leading to monolayer-like excitonic properties even in bulk crystals. While recent...journal article 2023
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Failla, M. (author), García Flórez, Fransisco (author), Salzmann, Bastiaan B.V. (author), Vanmaekelbergh, Daniel (author), Stoof, Henk T.C. (author), Siebbeles, L.D.A. (author)We studied the initial nature and relaxation of photoexcited electronic states in CdSe nanoplatelets (NPLs). Ultrafast transient optical absorption (TA) measurements were combined with the theoretical analysis of the formation and decay of excitons, biexcitons, free charge carriers, and trions. In the latter, photons and excitons were treated...journal article 2023
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Maiti, Sourav (author), Siebbeles, L.D.A. (author)In this Perspective, we provide an overview of recent advances in harvesting triplets for photovoltaic and photon upconversion applications from two angles. In singlet fission-sensitized solar cells, the triplets are harvested through a low band gap semiconductor such as Si. Recent literature has shown how a thin interlayer or orientation of...review 2023
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Maisel Licerán, Lucas (author), García Flórez, Francisco (author), Siebbeles, L.D.A. (author), Stoof, Henk T.C. (author)We analyze the topology, dispersion, and optical selection rules of bulk Wannier excitons in nanosheets of Bi<sub>2</sub>Se<sub>3</sub>, a topological insulator in the family of the bismuth chalcogenides. Our main finding is that excitons also inherit the topology of the electronic bands, quantified by the skyrmion winding numbers of the...journal article 2023
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Hempel, Hannes (author), Savenije, T.J. (author), Stolterfoht, Martin (author), Neu, Jens (author), Failla, M. (author), Paingad, Vaisakh C. (author), Kužel, Petr (author), Zhao, J. (author), Siebbeles, L.D.A. (author)Mobilities and lifetimes of photogenerated charge carriers are core properties of photovoltaic materials and can both be characterized by contactless terahertz or microwave measurements. Here, the expertise from fifteen laboratories is combined to quantitatively model the current-voltage characteristics of a solar cell from such measurements....journal article 2022
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Maiti, S. (author), Poonia, D. (author), Schall, Peter (author), Kinge, S.S. (author), Siebbeles, L.D.A. (author), van der Laan, M. (author)In conventional solar cell semiconductor materials (predominantlySi)photons with energy higher than the band gap initially generate hot electrons and holes, which subsequently cool down to the band edge by phonon emission. Due to the latter process,the energy of the charge carriers in excess of the band gap is lost as heat and does not...journal article 2021
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Manteiga Vázquez, Francisco (author), Yu, Qianli (author), Klepzig, Lars F. (author), Siebbeles, L.D.A. (author), Crisp, R.W. (author), Lauth, J.D. (author)Colloidal PbS nanoplatelets (NPLs) are highly interesting materials for near-infrared optoelectronic applications. We use ultrafast transient optical absorption spectroscopy to study the characteristics and dynamics of photoexcited excitons in ultrathin PbS NPLs with a cubic crystal structure. NPLs are synthesized at near room temperature...journal article 2021
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Poonia, D. (author), Singh, N. (author), Schulpen, Jeff J.P.M. (author), van der Laan, M. (author), Maiti, S. (author), Failla, M. (author), Kinge, S.S. (author), Bol, Ageeth A. (author), Schall, Peter (author), Siebbeles, L.D.A. (author)We studied the nature of excitons in the transition metal dichalcogenide alloy Mo0.6W0.4S2 compared to pure MoS2 and WS2 grown by atomic layer deposition (ALD). For this, optical absorption/transmission spectroscopy and time-dependent density functional theory (TDDFT) were used. The effects of temperature on A and B exciton peak energies and...journal article 2021
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Tang, Yingying (author), Poonia, D. (author), van der Laan, M. (author), Timmerman, Dolf (author), Kinge, S.S. (author), Siebbeles, L.D.A. (author), Schall, Peter (author)Assembled perovskite nanocrystals (NCs), known as supercrystals (SCs), can have many exotic optical and electronic properties different from the individual NCs due to energy transfer and electronic coupling in the dense superstructures. We investigate the optical properties and ultrafast carrier dynamics of highly ordered SCs and the...journal article 2021
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van der Laan, M. (author), De Weerd, Chris (author), Poirier, Lucas (author), van de Water, O.P. (author), Poonia, D. (author), Gomez, Leyre (author), Kinge, S.S. (author), Siebbeles, L.D.A. (author), Koenderink, A. Femius (author)Photon recycling, the iterative process of re-Absorption and re-emission of photons in an absorbing medium, can play an important role in the power-conversion efficiency of photovoltaic cells. To date, several studies have proposed that this process may occur in bulk or thin films of inorganic lead-halide perovskites, but conclusive proof of...journal article 2021
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Schiettecatte, Pieter (author), Poonia, D. (author), Tanghe, Ivo (author), Maiti, S. (author), Failla, M. (author), Kinge, S.S. (author), Hens, Zeger (author), Siebbeles, L.D.A. (author), Geiregat, Pieter (author)Few-layered transition-metal dichalcogenides (TMDs) are increasingly popular materials for optoelectronics and catalysis. Among the various types of TMDs available today, rhenium chalcogenides (ReX2) stand out due to their remarkable electronic structure, such as the occurrence of anisotropic excitons and potential direct band gap behavior...journal article 2021
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Maiti, S. (author), Poonia, D. (author), Schiettecatte, Pieter (author), Hens, Zeger (author), Geiregat, Pieter (author), Kinge, S.S. (author), Siebbeles, L.D.A. (author)We studied the dynamics of transfer of photoexcited electronic states in a bilayer of the two-dimensional transition metal dichalcogenide ReS2 and tetracene, with the aim to produce triplets in the latter. This material combination was used as the band gap of ReS2 (1.5 eV) is slightly larger than the triplet energy of tetracene (1.25 eV)....journal article 2021
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Kulkarni, A. (author), Evers, W.H. (author), Van Waas, Thomas P. (author), Siebbeles, L.D.A. (author)Lead selenide (PbSe) nanorods are of interest for applications in infrared LEDs, lasers, and photovoltaics due to the possibility of tuning their band gap from the far- to the near-infrared by decreasing their radius. We study the photogeneration quantum yield and properties of free charges and excitons in PbSe nanorods using a combination of...journal article 2020
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Failla, M. (author), García Flórez, Francisco (author), Salzmann, Bastiaan B.V. (author), Vanmaekelbergh, Daniel (author), Stoof, Henk T.C. (author), Siebbeles, L.D.A. (author)We show that the finite lateral sizes of ultrathin CdSe nanoplatelets strongly affect both their photoluminescence and optical absorption spectra. This is in contrast to the situation in quantum wells, in which the large lateral sizes may be assumed to be infinite. The lateral sizes of the nanoplatelets are varied over a range of a few to...journal article 2020
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Maiti, S. (author), Ferro, Silvia (author), Poonia, D. (author), Ehrler, Bruno (author), Kinge, S.S. (author), Siebbeles, L.D.A. (author)Carrier multiplication (CM) generates multiple electron-hole pairs in a semiconductor from a single absorbed photon with energy exceeding twice the band gap. Thus, CM provides a promising way to circumvent the Shockley-Queisser limit of solar cells. The ideal material for CM should have significant overlap with the solar spectrum and should...journal article 2020
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Crisp, R.W. (author), Hashemi, Fatemeh S.M. (author), Alkemade, J. (author), Kirkwood, N.R.M. (author), Grimaldi, G. (author), Kinge, S.S. (author), Siebbeles, L.D.A. (author), van Ommen, J.R. (author), Houtepen, A.J. (author)To improve the stability and carrier mobility of quantum dot (QD) optoelectronic devices, encapsulation or pore infilling processes are advantageous. Atomic layer deposition (ALD) is an ideal technique to infill and overcoat QD films, as it provides excellent control over film growth at the sub-nanometer scale and results in conformal...journal article 2020
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García Flórez, F. (author), Siebbeles, L.D.A. (author), Stoof, H. T.C. (author)We examine the impact of quantum confinement on the interaction potential between two charges in two-dimensional semiconductor nanosheets in solution. The resulting effective potential depends on two length scales, namely, the thickness d and an emergent length scale d∗ϵd/ϵsol, where ϵ is the permittivity of the nanosheet and ϵsol is the...journal article 2020