Article
Chemistry, Multidisciplinary
Zhu Meng, Benoit Mahler, Julien Houel, Florian Kulzer, Gilles Ledoux, Andrey Vasil'ev, Christophe Dujardin
Summary: The research found that in CdS/CdSe/CdS spherical quantum wells (SQWs) nanoscintillators, large-size SQWs can generate more excitons under X-ray excitation, but the increased Auger quenching effect makes large SQWs less effective in terms of timing performance.
Article
Chemistry, Physical
Jiakuan Zhang, Chuyue Li, Jiongzhao Li, Xiaogang Peng
Summary: Size- and shape-controlled CdSe/ZnSe core/shell and CdSe/ZnSe/ZnS core/shell/shell nanocrystals with zinc-blende structure are synthesized. The ligand strain between the inorganic crystal surface and organic ligands plays a key role in ZnSe epitaxy. The lattice strain between the CdSe and ZnSe affects the photoluminescence of CdSe/ZnSe/ZnS core/shell/shell QDs.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Shaojie Liu, Yufei Shu, Meiyi Zhu, Haiyan Qin, Xiaogang Peng
Summary: Most bulk semiconductors show an increase in band-gap energy with decreasing temperature. However, semiconductor quantum dots (QDs) exhibit non-monotonic temperature dependence of the emission energy at low temperatures. This study uses stable and efficient CdSe/CdS/ZnS QDs as a model system to quantitatively explain the origins of the anomalous emission red-shift at temperatures below 40 K. The red-shift is attributed to the temperature-dependent population of band-edge exciton fine levels, enhanced electron-optical phonon coupling due to increasing population of dark excitons, and temperature-dependent electron-acoustic phonon coupling.
Article
Chemistry, Multidisciplinary
Katherine E. Shulenberger, Sophie C. Coppieters 't Wallant, Megan D. Klein, Alexandra R. McIsaac, Tamar Goldzak, David B. Berkinsky, Hendrik Utzat, Ulugbek Barotov, Troy Van Voorhis, Moungi G. Bawendi
Summary: A spectrally resolved correlation method was developed to study the triply excited state, enabling direct measurements of the recombination pathway for the triexciton. It was found that for core-shell CdSe-CdS nanocrystals, triexciton emission arises exclusively from the band-edge S-like state. Time-dependent density functional theory and extended particle-in-a-sphere calculations show that reduced carrier overlap induced by the core-shell heterostructure can account for the lack of emission observed from the P-like state. These results provide insights for potential control of nanocrystal luminescence using core-shell heterostructures.
Article
Chemistry, Physical
Swati Khurana, Md Samim Hassan, Priyesh Yadav, Dibyajyoti Ghosh, Sameer Sapra
Summary: By utilizing bifunctional ligands, researchers synthesized MDNHs of CsPbBr3 nanocrystals and CdSe/CdS/ZnS core/shell/shell nanoplatelets, where 4-ATP exhibited faster charge transfer rate and the highest number of CSS NPLs around CsPbBr3 NCs in the MDNHs.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Physical
Yuzhe Wang, Yueqi Zhong, Jiangzhi Zi, Zichao Lian
Summary: In this study, CdSe@CdS@ZnS heterojunction nanocrystal hybrids were designed to improve the photoluminescence performance of conventional single-component quantum dots. The results demonstrate that the energy band structure is transformed and the photoluminescence lifetime and quantum efficiency are increased after the growth of ZnS.
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, 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
Chemistry, Physical
A. D. Kurilov, D. N. Chausov, V. V. Osipova, R. N. Kucherov, V. V. Belyaev, Y. G. Galyametdinov
Summary: This work focuses on synthesizing highly luminescent hybrid CdSe/CdS core/shell quantum dots and doping them into a nematic liquid crystal to obtain new composites. The sizes of the quantum dot cores and additional ZnS shells are correlated with the luminescence and dielectric characteristics of the composites.
JOURNAL OF MOLECULAR LIQUIDS
(2021)
Article
Chemistry, Multidisciplinary
Kai-Ping Chang, Yu-Cheng Yeh, Chung-Jui Wu, Chao-Chun Yen, Dong-Sing Wuu
Summary: CdSe/CdS core/shell quantum dots with different oleylamine (OLA) concentrations were synthesized using a one-pot method. The presence of ZnS diffraction peaks indicated the formation of a ZnS shell on the CdSe/CdS core. Interestingly, QDs with higher OLA concentration exhibited diffraction peaks of ZnS/ZnO, showing better thermal stability and slower decay in photoluminescence intensity. These QDs with tunable emission wavelength are suitable for micro-LED display applications.
Article
Polymer Science
Yuxiang Jiang, Chunyu Ji, Jiajia Wu, Qiurui Han, Chen Cui, Wenquan Shi, Zhili Peng
Summary: Despite their wide applications, the synthesis and photoluminescence mechanism of carbon dots (C-dots) have received less attention, limiting their further developments. In this study, C-dots were prepared from polyethylene glycol (PEG) with different molecular weights (M.W.), and the effects of PEG M.W. on the formation, structure, and optical properties of C-dots were carefully investigated. It was found that the particle sizes, fluorescence intensities, surface chemistry, thermal stability, and bioimaging capabilities of C-dots were significantly influenced by the PEG M.W. Moreover, these C-dots showed low cytotoxicity and promising potential for cellular bioimaging.
Article
Chemistry, Physical
E. Krishnan Vishnu, Anoop Ajaya Kumar Nair, K. George Thomas
Summary: The study investigates the photoluminescence fluctuations in CdSe QDs by varying core size and maintaining constant shell thickness. Increase in core size leads to enhanced detrapping rate and higher photoluminescence efficiency.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Multidisciplinary
Xiaoqi Hou, Haiyan Qin, Xiaogang Peng
Summary: Auger recombination is effectively reduced in high-quality quantum dots by enhancing dielectric screening of band-edge carriers with additional ZnS shells. The volume scaling of negative-trion Auger lifetime is achieved with ZnS shells, which can be less than half the volume of QDs without these shells, while also enhancing the biexciton emission quantum yield. The engineering of Auger effects through dielectric screening presents new opportunities for improving emission properties in multicarrier states of quantum dots.
Article
Chemistry, Analytical
Luping Tang, Yangyang Zhang, Chen Liao, Yingqing Guo, Yingtao Lu, Yixuan Xia, Yiwei Liu
Summary: In this study, the temperature-dependent photoluminescence (PL) properties of CdS/ZnS core/shell quantum dots (QDs) were investigated. The results showed that the band-edge emission (BEE) intensity decreased with increasing temperature, while the surface-state emission (SSE) intensity first increased and then decreased. The PL spectra exhibited a redshift in peak energies and an increase in full width at half-maximum (FWHM) as the temperature increased. Furthermore, the CIE chromaticity coordinates showed a dramatic change with temperature. These findings suggest that CdS/ZnS core/shell QDs have potential applications as temperature sensors.
Article
Chemistry, Applied
Mei Hu, Xiaofei Hu, Guoqiang Wang, Yongxia Cheng, Xiaoling Yu, Xianqing Huang, Yu Li
Summary: A portable fluorescence immunosensor based on CdSe/CdS/ZnS quantum dots (QDs) was developed for the precise quantification of olaquindox (OLA). The QDs labeled anti-OLA antibody served as a bioprobe and greatly enhanced the sensitivity of the lateral flow test strip. The method achieved quantitative results within 8 minutes using a fluorescent strip scan reader, with a detection limit of 0.12 μg/kg, 2.7 times more sensitive than the conventional colloidal gold-based strips. Acceptable recovery rates of 85.0%-95.5% were obtained for spiked samples. This QDs-based strip immunoassay method is suitable for on-site detection and rapid initial screening of OLA in swine feedstuff, and has the potential for detecting other veterinary drugs to ensure food safety.
Article
Chemistry, Multidisciplinary
Wonhyuk Jo, Fabian Westermeier, Rustam Rysov, Olaf Leupold, Florian Schulz, Steffen Tober, Verena Markmann, Michael Sprung, Allesandro Ricci, Torsten Laurus, Allahgholi Aschkan, Alexander Klyuev, Ulrich Trunk, Heinz Graafsma, Gerhard Grubel, Wojciech Roseker
Summary: X-ray photon correlation spectroscopy (XPCS) is a routine technique for studying slow dynamics in complex systems at storage-ring sources. Achieving nanosecond time resolution with conventional XPCS technique is challenging, but employing an adaptive gain integrating pixel detector (AGIPD) can enable nanosecond XPCS studies, marking an important step towards routine fast XPCS studies at storage rings.
Article
Chemistry, Multidisciplinary
Yulong Zhuang, Salah Awel, Anton Barty, Richard Bean, Johan Bielecki, Martin Bergemann, Benedikt J. Daurer, Tomas Ekeberg, Armando D. Estillore, Hans Fangohr, Klaus Giewekemeyer, Mark S. Hunter, Mikhail Karnevskiy, Richard A. Kirian, Henry Kirkwood, Yoonhee Kim, Jayanath Koliyadu, Holger Lange, Romain Letrun, Jannik Luebke, Abhishek Mall, Thomas Michelat, Andrew J. Morgan, Nils Roth, Amit K. Samanta, Tokushi Sato, Zhou Shen, Marcin Sikorski, Florian Schulz, John C. H. Spence, Patrik Vagovic, Tamme Wollweber, Lena Worbs, P. Lourdu Xavier, Oleksandr Yefanov, Filipe R. N. C. Maia, Daniel A. Horke, Jochen Kuepper, N. Duane Loh, Adrian P. Mancuso, Henry N. Chapman, Kartik Ayyer
Summary: One of the outstanding problems in X-ray single-particle imaging is the classification of structural heterogeneity. This paper proposes two methods that can account for orientation-induced variation and determine the structural landscape of a sample ensemble. The methods are validated using experimental data and can recover discrete structural classes and continuous deformations.
Article
Chemistry, Multidisciplinary
Yanan Kang, Leroy Marwin Nack, Yang Liu, Bing Qi, Yalan Huang, Ziyao Liu, Indranath Chakraborty, Florian Schulz, Abdullah A. A. Ahmed, Mirco Clavo Poveda, Fereshta Hafizi, Sathi Roy, Marina Mutas, Malte Holzapfel, Carlos Sanchez-Cano, K. David Wegner, Neus Feliu, Wolfgang J. Parak
Summary: Most studies on the interaction between nanoparticles (NPs) and cells have focused on how the physicochemical properties of NPs affect their uptake by the cells. However, there is limited understanding of the potential excretion of NPs from cells. To control and manipulate the number of NPs in a cell, both cellular uptake and excretion need to be quantitatively studied.
Article
Polymer Science
Marijana Ponjavic, Sanja Jevtic, Marija S. Nikolic
Summary: Multiblock copolymers comprising biodegradable polyesters poly(epsilon-caprolactone) (PCL) and poly(butylene succinate) (PBS) were successfully synthesized through chain-extension reaction. The composition and structure of these copolymers significantly influenced their biodegradability properties.
JOURNAL OF POLYMER RESEARCH
(2022)
Article
Chemistry, Multidisciplinary
Ferdinand Otto, Xing Sun, Florian Schulz, Carlos Sanchez-Cano, Neus Feliu, Fabian Westermeier, Wolfgang J. Parak
Summary: X-ray photon correlation spectroscopy is used to determine the hydrodynamic diameters of gold nanoparticles in biological environments, providing an in situ method that overcomes the limitations of traditional visible light detection techniques.
Article
Polymer Science
Olga Pantic, Milica Spasojevic, Enis Dzunuzovic, Marija S. Nikolic, Sanja Savic, Maja Markovic, Pavle Spasojevic
Summary: The present study aimed to prepare fully bio-based unsaturated polyester resins (UPRs) with comparable properties to commercial formulas. The optimal prepolymer formulation using the same set of diacids and different diols or mixtures was determined, and bio-based dimethyl itaconate was used as a reactive diluent. The obtained resins were analyzed for their rheology, structural, thermal, thermomechanical, and mechanical properties. The choice of diols in the prepolymer formulation was found to significantly affect the properties of the UPRs.
Correction
Chemistry, Multidisciplinary
Yanan Kang, Leroy Nack, Yang Liu, Bing Qi, Yalan Huang, Ziyao Liu, Indranath Chakraborty, Florian Schulz, Abdullah Ahmed, Mirco Clavo Poveda, Fereshta Hafizi, Sathi Roy, Marina Mutas, Malte Holzapfel, Carlos Sanchez Cano, K. David Wegner, Neus Feliu, Wolfgang J. Parak
Article
Chemistry, Physical
Avni Jain, Florian Schulz, Francesco Dallari, Verena Markmann, Fabian Westermeier, Yugang Zhang, Gerhard Gruebel, Felix Lehmkuehler
Summary: In this study, the gelation of PEGylated gold nanoparticles dispersed in a glycerol-water mixture was investigated in situ by x-ray photon correlation spectroscopy. The results reveal a three-step gelation process, including the simultaneous changes of structure and dynamics, establishment of gel network structure, and aging after the arrest of particle motion. Additionally, the gelation process is characterized by stress release.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Florian Schulz, Holger Lange
Summary: Periodic arrangements of plasmonic nanoparticles in supercrystals exhibit strong light-matter interaction. This study analyzes experimental data to investigate the reproducibility and tunability of gap sizes in relation to the particle diameter and molecular weight of stabilizing ligands. Different behaviors of polystyrene-based ligands are observed depending on their molecular weight, leading to important consequences for the correlation between nanoparticle diameter and resulting gaps in supercrystals. An alternative volume-based approach is proposed for predicting gap sizes in larger nanoparticles, which provides robust guidelines for achieving gaps below 5 nm for enhanced light-matter coupling.
ADVANCED OPTICAL MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Jhoan Toro-Mendoza, Lucia Maio, Marta Gallego, Ferdinand Otto, Florian Schulz, Wolfgang J. Parak, Carlos Sanchez-Cano, Ivan Coluzza
Summary: Nanoparticles and other nano-materials have potential as nanodrugs or nanomedical devices, but their therapeutic response can be significantly affected by protein adsorption. By combining experimental and computational approaches, we have developed nanoparticles with polyethylene glycol (PEG) coatings that mimic the surface charge distribution of proteins in blood, showing low aggregation under normal blood conditions.
Article
Chemistry, Physical
Finn Hoeeg, Jennifer Schulz, Sebastian Graf, Dina Salah, Sharah Chandralingam, Wolfgang Maison, Wolfgang J. Parak, Florian Schulz
Summary: This study investigates the surface chemistry of gold nanoparticles using gel electrophoresis. It is found that coadsorption of PEG ligands significantly reduces protein adsorption and matrix effects of cell media, improving the colloidal stability of nanoparticles. The controlled adsorption of PEG ligands with different molecular weights allows for the disentanglement of particle charge and hydrodynamic diameter effects.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Multidisciplinary
Dominik Hoeing, Robert Salzwedel, Lena Worbs, Yulong Zhuang, Amit K. K. Samanta, Jannik Lubke, Armando D. D. Estillore, Karol Dlugolecki, Christopher Passow, Benjamin Erk, Nagitha Ekanayake, Daniel Ramm, Jonathan Correa, Christina C. Papadopoulou, Atia Tul Noor, Florian Schulz, Malte Selig, Andreas Knorr, Kartik Ayyer, Jochen Kupper, Holger Lange
Summary: Currently, the dynamics of optically excited plasmonic nanoparticles are explained as a series of scattering events caused by nanoparticle breathing oscillations initiated by statistical heat transfer from thermalized electrons to the lattice. However, a phase mismatch between theory and experiments suggests an additional excitation mechanism. Through optical transient absorption spectroscopy and time-resolved single-particle X-ray diffractive imaging, we found that optically induced electron density gradients are the initial driving source for breathing oscillation and confirmed the need for an additional excitation mechanism for thermal expansion. Our new model reproduces all experimental observations.
Review
Chemistry, Multidisciplinary
Florian Schulz, Jonas Huehn, Marco Werner, Dominik Huehn, Julia Kvelstad, Ulrich Koert, Nicole Wutke, Markus Klapper, Michael Froeba, Vladimir Baulin, Wolfgang J. J. Parak
Summary: The ligand shell of colloidal nanoparticles serves various purposes, including providing colloidal stability and creating a local environment different from the bulk solvent. This local environment has profound implications for sensing applications and can modulate specific responses.
ACCOUNTS OF CHEMICAL RESEARCH
(2023)
Article
Chemistry, Physical
Matias Herran, Sabrina Juergensen, Moritz Kessens, Dominik Hoeing, Andrea Koeppen, Ana Sousa-Castillo, Wolfgang J. Parak, Holger Lange, Stephanie Reich, Florian Schulz, Emiliano Cortes
Summary: The researchers present a two-dimensional bimetallic catalyst for efficient hydrogen generation under visible light illumination and solar irradiance by incorporating platinum nanoparticles into a well-defined supercrystal of gold nanoparticles. They observe a correlation between the intensity of the electric field in the hotspots and the boosted catalytic activity of platinum nanoparticles, while identifying a minor role of heat and gold-to-platinum charge transfer in the enhancement.
Review
Chemistry, Analytical
I. Brian Becerril-Castro, Irene Calderon, Nicolas Pazos-Perez, Luca Guerrini, Florian Schulz, Neus Feliu, Indranath Chakraborty, Vincenzo Giannini, Wolfgang J. Parak, Ramon A. Alvarez-Puebla
Summary: Gold nanostars are efficient plasmonic nanomaterials for optical sensing, and their importance has been increasing in various fields. Due to their exotic shape and characteristics, these nanoparticles can be used for optical enhancement and catalysis.
ANALYSIS & SENSING
(2022)
