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Vogel, Y.B. (author), Pham, Le Nhan (author), Stam, M. (author), Ubbink, R.F. (author), Coote, Michelle L. (author), Houtepen, A.J. (author)The optoelectronic properties of colloidal quantum dots (cQDs) depend critically on the absolute energy of the conduction and valence band edges. It is well known these band-edge energies are sensitive to the ligands on the cQD surface, but it is much less clear how they depend on other experimental conditions, like solvation. Here, we...journal article 2024
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Mulder, J.T. (author), Meijer, M.S. (author), van Blaaderen, J.J. (author), du Fossé, I. (author), Jenkinson, Kellie (author), Bals, Sara (author), Manna, Liberato (author), Houtepen, A.J. (author)Ytterbium-doped LiYF4 (Yb:YLF) is a commonly used material for laser applications, as a photon upconversion medium, and for optical refrigeration. As nanocrystals (NCs), the material is also of interest for biological and physical applications. Unfortunately, as with most phosphors, with the reduction in size comes a large reduction of the...journal article 2023
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Brosseau, Patrick J. (author), Geuchies, J.J. (author), Jasrasaria, Dipti (author), Houtepen, A.J. (author), Rabani, Eran (author), Kambhampati, Patanjali (author)Elucidating the population dynamics of correlated electron-hole pairs (bound excitons) in semiconducting quantum dots (QDs) is key for developing our fundamental understanding of nanoscale photophysics as well as for the optimal design of devices, such as lasers. For decades, it was assumed that holes did not contribute to band edge bleach...journal article 2023
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Llusar, Jordi (author), du Fossé, I. (author), Hens, Zeger (author), Houtepen, A.J. (author), Infante, Ivan (author)Although density functional theory (DFT) calculations have been crucial in our understanding of colloidal quantum dots (QDs), simulations are commonly carried out on QD models that are significantly smaller than those generally found experimentally. While smaller models allow for efficient study of local surface configurations, increasing the...journal article 2023
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Mangnus, Mark J.J. (author), de Wit, Jur W. (author), Vonk, Sander J.W. (author), Geuchies, J.J. (author), Albrecht, Wiebke (author), Bals, Sara (author), Houtepen, A.J. (author), Rabouw, Freddy T. (author)In recent years, quantum dots (QDs) have emerged as bright, color-tunable light sources for various applications such as light-emitting devices, lasing, and bioimaging. One important next step to advance their applicability is to reduce particle-to-particle variations of the emission properties as well as fluctuations of a single QD’s...journal article 2023
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Zhang, Heng (author), Debroye, Elke (author), Fu, Shuai (author), González, Miriam C.Rodriguez (author), du Fossé, I. (author), Geuchies, Jaco J. (author), Gao, Lei (author), Yu, Xiaoqing (author), Houtepen, A.J. (author)Synergically combining their respective ultrahigh charge mobility and strong light absorption, graphene (Gr)/semiconductor heterostructures are promising building blocks for efficient optoelectronics, particularly photodetectors. Charge transfer (CT) across the heterostructure interface crucially determines device efficiency and functionality...journal article 2023
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Ubbink, R.F. (author), Gudjónsdóttir, S. (author), Vogel, Y.B. (author), Houtepen, A.J. (author)Electrochemical charging of nanocrystal films opens up new possibilities for designing quantum dot-based device structures, but a solid theoretical framework of this process and its limitations is lacking. In this work, drift-diffusion simulations are employed to model the charging of nanocrystal films and gain insight into the...journal article 2023
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Mulder, J.T. (author), Jenkinson, Kellie (author), Toso, Stefano (author), Prato, Mirko (author), Evers, W.H. (author), Bals, Sara (author), Manna, Liberato (author), Houtepen, A.J. (author)Lanthanide-doped LiYF4 (Ln:YLF) is commonly used for a broad variety of optical applications, such as lasing, photon upconversion and optical refrigeration. When synthesized as nanocrystals (NCs), this material is also of interest for biological applications and fundamental physical studies. Until now, it was unclear how Ln:YLF NCs grow from...journal article 2023
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Wei, Z. (author), Mulder, J.T. (author), Dubey, R. (author), Evers, W.H. (author), Jager, W.F. (author), Houtepen, A.J. (author), Grozema, F.C. (author)Understanding the interplay between the kinetics and energetics of photophysical processes in perovskite-chromophore hybrid systems is crucial for realizing their potential in optoelectronics, photocatalysis, and light-harvesting applications. By combining steady-state optical characterizations and transient absorption spectroscopy, we have...journal article 2023
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Almeida, Guilherme (author), van der Poll, L.M. (author), Evers, W.H. (author), Szoboszlai, Emma (author), Vonk, Sander J.W. (author), Rabouw, Freddy T. (author), Houtepen, A.J. (author)Indium phosphide colloidal quantum dots (CQDs) are the main alternative for toxic and restricted Cd based CQDs for lighting and display applications. Here we systematically report on the size-dependent optical absorption, ensemble, and single particle photoluminescence (PL) and biexciton lifetimes of core-only InP CQDs. This systematic study...journal article 2023
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Gonçalves Pereira Fonseca DeAl, G.P.F. (author), Ubbink, R.F. (author), Stam, M. (author), du Fossé, I. (author), Houtepen, A.J. (author)Owing to their tunable band gap, high absorption coefficient, narrow emission linewidths and unrestricted composition, InP-based colloidal quantum dots (QDs) have become industrially relevant for visible and near-infrared photonic technologies. Although their development has so far been strongly driven by their suitability for green and red...review 2023
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Stam, M. (author), du Fossé, I. (author), Infante, Ivan (author), Houtepen, A.J. (author)Quantum dots (QDs) are known for their size-dependent optical properties, narrow emission bands, and high photoluminescence quantum yield (PLQY), which make them interesting candidates for optoelectronic applications. In particular, InP QDs are receiving a lot of attention since they are less toxic than other QD materials and are hence...journal article 2023
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du Fossé, I. (author), Mulder, J.T. (author), Almeida, Guilherme (author), Spruit, Anne G.M. (author), Infante, Ivan (author), Grozema, F.C. (author), Houtepen, A.J. (author)One of the most promising properties of lead halide perovskite nanocrystals (NCs) is their defect tolerance. It is often argued that, due to the electronic structure of the conduction and valence bands, undercoordinated ions can only form localized levels inside or close to the band edges (i.e., shallow traps). However, multiple studies have...journal article 2022
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Geuchies, J.J. (author), Dijkhuizen, Robbert (author), Koel, Marijn (author), Grimaldi, G. (author), du Fossé, I. (author), Evers, W.H. (author), Hens, Zeger (author), Houtepen, A.J. (author)Colloidal nanoplatelets (NPLs) are promising materials for lasing applications. The properties are usually discussed in the framework of 2D materials, where strong excitonic effects dominate the optical properties near the band edge. At the same time, NPLs have finite lateral dimensions such that NPLs are not true extended 2D structures. Here...journal article 2022
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Vogel, Y.B. (author), Stam, M. (author), Mulder, J.T. (author), Houtepen, A.J. (author)We present a strategy to actively engineer long-range charge transport in colloidal quantum dot assemblies by using ligand functionalities that introduce electronic states and provide a path for carrier transfer. This is a shift away from the use of inactive spacers to modulate charge transport through the lowering of the tunneling barrier...journal article 2022
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Ubbink, R.F. (author), Gonçalves Pereira Fonseca DeAl, G.P.F. (author), Iziyi, Hodayfa (author), du Fossé, I. (author), Verkleij, Ruud (author), Ganapathy, S. (author), Van Eck, Ernst R.H. (author), Houtepen, A.J. (author)Indium phosphide quantum dots are the main alternative for toxic and restricted Cd-based quantum dots for lighting and display applications, but in the absence of protecting ZnSe and/or ZnS shells, InP quantum dots suffer from low photoluminescence quantum yields. Traditionally, HF treatments have been used to improve the quantum yield of InP...journal article 2022
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Eren, H. (author), Bednarz, Roland Jan Reiner (author), Alimoradi Jazi, M. (author), Donk, Laura (author), Gudjónsdóttir, S. (author), Bohländer, P.R. (author), Eelkema, R. (author), Houtepen, A.J. (author)Quantum dots (QDs) are considered for devices like light-emitting diodes (LEDs) and photodetectors as a result of their tunable optoelectronic properties. To utilize the full potential of QDs for optoelectronic applications, control over the charge carrier density is vital. However, controlled electronic doping of these materials has remained...journal article 2022
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Rademacher, Markus (author), Gosling, Jonathan (author), Pontin, Antonio (author), Toroš, Marko (author), Mulder, J.T. (author), Houtepen, A.J. (author), Barker, P. F. (author)We demonstrate the measurement of nanoparticle anisotropy by angularly resolved Rayleigh scattering of single optical levitated particles that are oriented in space via the trapping light in vacuum. This technique is applied to a range of particle geometries from perfect spherical nanodroplets to octahedral nanocrystals. We show that this...journal article 2022
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Vonk, Sander J.W. (author), Heemskerk, Bart A.J. (author), Keitel, Robert C. (author), Hinterding, Stijn O.M. (author), Geuchies, J.J. (author), Houtepen, A.J. (author), Rabouw, Freddy T. (author)Broadening of multiexciton emission from colloidal quantum dots (QDs) at room temperature is important for their use in high-power applications, but an in-depth characterization has not been possible until now. We present and apply a novel spectroscopic method to quantify the biexciton line width and biexciton binding energy of single CdSe...journal article 2021
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Fu, Shuai (author), du Fossé, I. (author), Jia, Xiaoyu (author), Xu, Jingyin (author), Yu, Xiaoqing (author), Zhang, Heng (author), Zheng, Wenhao (author), Krasel, Sven (author), Houtepen, A.J. (author)Van der Waals heterostructures consisting of graphene and transition metal dichalcogenides have shown great promise for optoelectronic applications. However, an in-depth understanding of the critical processes for device operation, namely, interfacial charge transfer (CT) and recombination, has so far remained elusive. Here, we investigate...journal article 2021