Article
Chemistry, Physical
David F. Macias-Pinilla, Josep Planelles, Ivan Mora-Sero, Juan Climente
Summary: This study investigates the optoelectronic properties of metal chalcogenide colloidal nanoplatelets, revealing the presence of trion states in addition to excitonic states. The analysis shows how the additional charge in trions modifies emission energy and oscillator strength compared to neutral excitons, with properties sensitive to dielectric confinement and electronic correlations. Experimental and theoretical results are consistent, further evaluating the validity of previous theoretical approximations.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Multidisciplinary
Alexandra Brumberg, Nicolas E. Watkins, Benjamin T. Diroll, Richard D. Schaller
Summary: Colloidal semiconductor nanocrystals, such as CdSe nanoplatelets and quantum dots, offer advantages in optoelectronics but are affected by rapid nonradiative Auger recombination at high excitation intensities. This study investigates the temperature dependence of excited state lifetime and fluence-dependent emission, revealing fundamental differences between CdSe nanoplatelets and core-only quantum dots, and highlighting the increased utility of photogenerated excitons and multiexcitons at low temperatures.
Article
Chemistry, Multidisciplinary
Albert F. Vong, Shawn Irgen-Gioro, Yue Wu, Emily A. Weiss
Summary: Colloidal semiconductor nanoplatelets are scalable materials for optoelectronic applications and can be used for spin-to-photon transduction in quantum information networks. Negative trions are appealing emitters, but more preparation knowledge is needed to use them as single photon-emitting states. Through power-dependent time-resolved transient absorptions, it was shown that trions form via biexciton decay and not through collisional mechanisms typical for 2D materials.
Article
Chemistry, Physical
Lifeng Wang, Dongmei Xiang, Kaimin Gao, Junhui Wang, Kaifeng Wu
Summary: Colloidal n-doped CdSe and CdSe/ZnS nanoplatelets have been achieved through a photochemical doping method, demonstrating successful additional electron doping at the conduction band edge. The key to successful doping lies in a high surface ligand coverage, while unpassivated surface cations may lead to depletion of the doped electrons.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Physical
Z. Ouzit, G. Baillard, J. Liu, B. Wagnon, L. Guillemeney, B. Abecassis, L. Coolen
Summary: This study compares the luminescence decay dynamics of single CdSe nanoplatelets, clusters of a few platelets, and self-assembled chains. The luminescence decay becomes faster as the number of stacked platelets increases, indicating the FRET-mediated effect of quenchers. Additionally, a slow decay component is observed for both single platelets and platelet chains, suggesting trapping-detrapping mechanisms in nearby trap states. Toy models are developed to analyze the effects of FRET-mediated quenching and trapping on decay curves.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Dongmei Xiang, Yulu Li, Lifeng Wang, Tao Ding, Junhui Wang, Kaifeng Wu
Summary: In this study, the electron and hole spin dynamics in CdSe colloidal nanoplatelets of varying thicknesses were investigated using circularly polarized transient absorption spectroscopy. The results showed that hole spin-flip occurred within 200 fs, while the electron spin lifetime decreased as the platelet thickness was reduced. The findings suggest an exchange interaction between the electron and the hole, and/or surface dangling bond spins enhanced by quantum confinement.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Physical
Nicolas E. Watkins, Jun Guan, Benjamin T. Diroll, Kali R. Williams, Richard D. Schaller, Teri W. Odom
Summary: This paper explores low-threshold lasing from colloidal CdSe nanoplatelets coated on two-dimensional plasmonic cavities composed of aluminum nanoparticles, demonstrating lasing action with low angular divergence, narrow spectral line width, and a threshold of around 200 mu J/cm(2). The research highlights the importance of designing nanoparticle lattices to support surface lattice resonances for achieving lasing.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Physical
Haochen Sun, Paul Cavanaugh, Ilan Jen-La Plante, Christian Ippen, Maria Bautista, Ruiqing Ma, David F. Kelley
Summary: Transient absorption and time-resolved photoluminescence spectroscopies were used to study the hole tunneling and Auger dynamics in high-quality InP/ZnSe/ZnS quantum dots. The study revealed that trapped holes can tunnel into the valence band, converting one type of biexciton to another type.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Andrew A. Marder, James Cassidy, Dulanjan Harankahage, Jacob Beavon, Luis Gutierrez-Arzaluz, Omar F. Mohammed, Aditya Mishra, Austen C. Adams, Jason. D. Slinker, Zhongjian Hu, Stephen Savoy, Mikhail Zamkov, Anton V. Malko
Summary: Compared to zero-dimensional (0D) semiconductor quantum dots, 2D semiconductor nanoplatelets (NPLs) offer a spectrally narrow luminescence and superior absorption coefficients. However, optical devices based on NPLs still suffer from nonradiative Auger decay, which limits the efficiency of various processes. In this study, it is demonstrated that Auger recombination is strongly suppressed in spherically shaped nanoplatelets called quantum shells (QSs), leading to improved performance in terms of biexciton emission yield, amplified spontaneous emission, and electroluminescence enhancement. These results are significant for the development of solution-processed colloidal lasers and LEDs.
ACS MATERIALS LETTERS
(2023)
Article
Nanoscience & Nanotechnology
Carolina Villamil Franco, Benoit Mahler, Christian Cornaggia, Thomas Gustavsson, Elsa Cassette
Summary: Understanding multiple exciton interactions and dynamics in semiconductor nanostructures is crucial for their use in light convertors. Investigations on 2D lead iodide perovskite nanoplatelets showed that nonradiative Auger recombination is the dominant pathway for multiexciton recombination, with dynamics subquadratic with exciton density. High excitation fluence leads to faster recombination rates.
ACS APPLIED NANO MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Taehee Kim, Yu-Ho Won, Eunjoo Jang, Dongho Kim
Summary: The study reveals that the Auger recombination processes of InP/ZnSe/ZnS quantum dots are influenced by the midshell structures, ultimately affecting the performance of QD-LEDs. The midshell thickness impacts the exciton-exciton binding energy and the negative trion Auger recombination behavior.
Article
Chemistry, Multidisciplinary
Nemanja Peric, Yannick Lambert, Shalini Singh, Ali Hossain Khan, Nathali Alexandra Franchina Vergel, Dominique Deresmes, Maxime Berthe, Zeger Hens, Iwan Moreels, Christophe Delerue, Bruno Grandidier, Louis Biadala
Summary: Through experiments and calculations, it was found that individual CdSe nanoplatelets exhibit peaks instead of the typical step-like function associated with quantum wells, indicating restricted electron motion. This finding, along with the detection of deep trap states on the edge facets, provides insights into the lateral confinement in quantum wells with finite dimensions.
Article
Chemistry, Physical
Da-Eun Yoon, Juho Lee, Hyeonwoo Yeo, Junga Ryou, Young Kuk Lee, Yong-Hoon Kim, Doh C. Lee
Summary: Shape anisotropy in colloidal zincblende CdSe nanoplatelets directly affects their optical and electronic properties. The lateral aspect ratio of NPLs provides a way to control their optical characteristics, such as polarized emission, by varying the shape while keeping the thickness constant. Experimental and simulation studies have shown that the growth behavior of CdSe NPLs can be altered by adjusting the Cd(ac)(2)-to-Se precursor ratio, leading to different growth directions. The mechanism for the lateral growth of zincblende NPLs has been explained at the atomic level, shedding light on the transition processes of NPL morphology and growth direction.
CHEMISTRY OF MATERIALS
(2021)
Article
Chemistry, Physical
Yonglei Sun, Hua Zhu, Na Jin, Ou Chen, Jing Zhao
Summary: Lifetime blinking, a phenomenon of fluctuations in the fluorescence lifetime of a single quantum dot over time while its fluorescence intensity remains relatively stable, has been reported in a few QD systems. In this study, statistical methods demonstrate that compact CdSe/CdS core/shell QDs also exhibit short-lived lifetime blinking events, possibly due to the activation of efficient nonradiative processes leading to intensity blinking.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Multidisciplinary
Benjamin T. Diroll, James P. Cassidy, Dulanjan Harankahage, Muchuan Hua, Xiao-Min Lin, Mikhail Zamkov
Summary: This study investigates the two-photon properties of colloidal quantum shells, specifically the CdS/CdSe/CdS quantum shell samples. The results show that these quantum shells exhibit large non-linear absorption cross-sections and advantageous multiexciton physics. They have potential applications in upconversion imaging and can be utilized as excellent gain media for two-photon excitation. Additionally, quantum shell solids support multimodal amplified spontaneous emission due to their broad gain bandwidth and long gain lifetime.
Article
Nanoscience & Nanotechnology
Marianne Aellen, Aurelio A. Rossinelli, Robert C. Keitel, Raphael Brechbuhler, Felipe Antolinez, Sergio G. Rodrigo, Jian Cui, David J. Norris
Summary: The researchers studied the effect of gain on the lasing behavior in plasmonic lasers by placing a semiconductor gain layer near a metallic interface. They found that the thickness of the gain layer determines the nature of the lasing mode, and a gap layer with a high refractive index can be advantageous for plasmonic lasing.
Article
Chemistry, Physical
Ario Cocina, Raphael Brechbuhler, Sander J. W. Vonk, Jian Cui, Aurelio A. Rossinelli, Henar Rojo, Freddy T. Rabouw, David J. Norris
Summary: In this study, a nanophotonic approach was used to enhance the characterization of decay processes in semiconductor nanocrystals, addressing open questions related to their emission. By varying the distance between nanocrystals and a gold reflector, the radiative rates were affected through changes in the local density of optical states. The method was applied to CdSe-based nanocrystals to investigate their radiative efficiency, polarization properties, and emission dynamics. The trapping mechanism responsible for delayed emission in CdSe-based nanoplatelets was also identified.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Johanna C. van der Bok, P. Tim Prins, Federico Montanarella, D. Nicolette Maaskant, Floor A. Brzesowsky, Maaike M. van der Sluijs, Bastiaan B. Salzmann, Freddy T. Rabouw, Andrei Petukhov, Celso De Mello Donega, Daniel Vanmaekelbergh, Andries Meijerink
Summary: Researchers found through in situ studies that in the early stage of the CdSe nanoplatelet reaction, both isotropic nanocrystals and mini-nanoplatelets form in the absence of short-chain ligands, but most precursors are consumed in isotropic growth. The addition of acetate induces a dramatic shift towards nearly exclusive 2D growth of already existing mini-nanoplatelets. Therefore, mature nanoplatelets only grow through a subtle interplay between myristate and acetate, with the latter catalyzing fast lateral growth of the side facets of the mini-nanoplatelets.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Multidisciplinary Sciences
Deepankur Thureja, Atac Imamoglu, Tomasz Smolenski, Ivan Amelio, Alexander Popert, Thibault Chervy, Xiaobo Lu, Song Liu, Katayun Barmak, Kenji Watanabe, Takashi Taniguchi, David J. Norris, Martin Kroner, Puneet A. Murthy
Summary: This study demonstrates electrically controlled quantum confinement of neutral excitons in 2D semiconductors, achieving confinement below 10 nm. The technique provides an experimental route towards creating scalable arrays of identical single-photon sources and has wide-ranging implications for realizing strongly correlated photonic phases and on-chip optical quantum information processors.
Article
Nanoscience & Nanotechnology
Thomas P. van Swieten, Andries Meijerink, Freddy T. Rabouw
Summary: This study demonstrates the importance of considering factors such as temperature sensitivity, luminescence strength, noise, and background signal for the precision of temperature measurement with luminescent nanocrystals. By determining the noise characteristics of the instrumentation, the uncertainty of temperature measurement can be quantitatively predicted.
Article
Multidisciplinary Sciences
J. J. Erik Maris, Freddy T. Rabouw, Bert M. Weckhuysen, Florian Meirer
Summary: Single-particle tracking is a powerful method for studying the motion of individual molecules and particles. The DiffusionLab software package provides motion analysis tools for challenging data sets, allowing trajectory classification based on motion type and computation of diffusion constants.
SCIENTIFIC REPORTS
(2022)
Article
Chemistry, Physical
P. Tim Prins, Dirk A. W. Spruijt, Mark J. J. Mangnus, Freddy T. Rabouw, Daniel Vanmaekelbergh, Celso de Mello Donega, Pieter Geiregat
Summary: Impurity doping of III-V colloidal quantum dots remains underexplored. This study shows that electron cooling is fast in copper-doped InP quantum dots, while hole localization is slow but still leads to efficient luminescence.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Bas J. P. Terlingen, Tjom Arens, Thomas P. P. van Swieten, Freddy T. T. Rabouw, P. Tim Prins, Michiel M. M. de Beer, Andries Meijerink, Mathieu P. P. Ahr, Eline M. M. Hutter, Coert E. J. van Lare, Bert M. M. Weckhuysen
Summary: In the field of heterogeneous catalysis, the temperature of the reactor or reaction medium is often reported, but it may vary significantly from the temperature of the reactive catalyst. The interplay between catalyst temperature and catalytic performance is not always accurately known. This study uses EuOCl as both a solid catalyst and a thermometer to determine temperature during operation. The results reveal the dynamics of catalyst temperature in relation to reaction conditions and provide insights into heat dissipation mechanisms. This approach of operando catalyst thermometry can enhance understanding of catalyst performance and improve safety in chemical industries.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Optics
Hector Monin, Aurelian Loirette-Pelous, Eva De Leo, Aurelio A. Rossinelli, Ferry Prins, David J. Norris, Elise Baily, Jean-Paul Hugonin, Benjamin Vest, Jean-Jacques Greffet
Summary: We investigate the light emission of a patterned ensemble of colloidal quantum dots (cQDs) through experimental and theoretical study. Compared to a planar layer of cQDs, this system significantly modifies the emission spectrum and polarization. It demonstrates bright, directional, and polarized emission, including circular polarization in certain directions. We propose a light emission model based on a local Kirchhoff law, which accurately reproduces all experimental features. This model provides a quantitative figure of merit for assessing the emitted power. This work facilitates the systematic design of efficient ultrathin light emitting metasurfaces with controlled polarization, spectrum, and directivity.
Article
Nanoscience & Nanotechnology
Marianne Aellen, David J. Norris
Summary: This article discusses the extraction of optical gain in photonic amplifiers and lasers, focusing on the confinement factor. A more general and accurate description of the confinement factor is proposed and its validity and limitations are examined through numerical examples. The findings highlight the importance of using the general formula for accurate characterization, particularly in the design of nanophotonic and plasmonic devices.
Article
Nanoscience & Nanotechnology
Carin R. Lightner, Filip Desmet, Daniel Gisler, Stefan A. Meyer, Ariel Francis Perez Mellor, Hannah Niese, Arnulf Rosspeintner, Robert C. Keitel, Thomas Burgi, Wouter A. Herrebout, Christian Johannessen, David J. Norris
Summary: Spectroscopic techniques can provide information about the chiral structure of molecules, but small errors in optical polarization control can lead to experimental artifacts. This study focuses on Raman optical activity (ROA) as an example and comprehensively investigates chiroptical artifacts. Based on the findings, standard controls are proposed to help researchers better understand, identify, and avoid experimental artifacts.
Article
Chemistry, Multidisciplinary
P. Tim Prins, Johanna C. van Der Bok, Thomas P. van Swieten, Stijn O. M. Hinterding, Andy J. Smith, Andrei V. Petukhov, Andries Meijerink, Freddy T. Rabouw
Summary: The synthesis of beta-NaYF4 nanocrystals from alpha-NaYF4 precursor particles was investigated using in situ small-angle and wide-angle X-ray scattering and ex situ electron microscopy. It was observed that the particle size distribution evolved from unimodal to bimodal, and eventually back to unimodal, with the final distribution being narrower than the initial distribution. The splitting of the size distribution was attributed to variations in the reactivity of the precursor particles.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Daniel Amgar, Gur Lubin, Gaoling Yang, Freddy T. T. Rabouw, Dan Oron
Summary: Semiconductor nanocrystal emission polarization is a crucial factor for nanocrystal-based technologies. A direct characterization method of the doubly excited-state relaxation transition dipole is proposed using heralded defocused imaging. The results reveal different transition dipole moments for different types of nanorods.
Article
Nanoscience & Nanotechnology
Mark J. J. Mangnus, Jur W. de Wit, Sander J. W. Vonk, Jaco J. Geuchies, Wiebke Albrecht, Sara Bals, Arjan J. Houtepen, Freddy T. Rabouw
Summary: Quantum dots (QDs) have emerged as bright and color-tunable light sources for various applications. Multiparticle spectroscopy (MPS) is demonstrated as a high-throughput method to acquire statistically relevant information about the emissions of QDs. CdSe-based QDs show narrower line widths, less spectral diffusion, and less inhomogeneous broadening compared to InP-based QDs. The experiments pave the way for large-scale characterization of single-QD emission properties and the rational design of future QD structures.
