Article
Physics, Multidisciplinary
Jordi Llusar, Juan I. Climente
Summary: Colloidal semiconductor nanoplatelets exhibit excellent optical emission properties due to their quasi-2D structures and strong in-plane Coulomb interactions. The charging of nanoplatelets with interacting fermions leads to severe Coulomb repulsions, resulting in strong electronic correlations and exchange energies. These phenomena give rise to characteristic physical effects such as deviating shell filling spectra, large addition energies for deterministic control of the number of charges, and activation of paramagnetic electron spin configuration at cryogenic temperatures.
PHYSICAL REVIEW LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Guiju Liu, Wenshuang Liang, Xuyan Xue, Federico Rosei, Yiqian Wang
Summary: Various imaging techniques are employed to characterize the core@shell structure of CdSe@CdS quantum dots with different CdS shell thicknesses. For thin-shelled QDs, a coherent interface forms between core and shell, while for thick-shelled QDs, although the lattice spacing is different at the core and shell regions, the heterostructured interface remains coherent and cannot be clearly imaged. With further increase in shell thickness, a sharp core@shell interface is observed.
Article
Optics
Yanqing Zhu, Cong Shen, Xueqing Xu, Jianhua Zou, Lei Wang, Xudong Cheng, Jingqiu Liang, Xiudi Xiao, Gang Xu
Summary: This study investigates the effect of halogen acid treatment on the luminescence properties of InP/GaP/ZnS quantum dots (QDs). It is found that hydrofluoric acid (HF) and hydrochloric acid (HCl) can improve the optical properties of QDs, while hydrobromic acid (HBr) and hydroiodic acid (HI) are not conductive to enhance the photoluminescence quantum yield (PL QY) of QDs. HF and HCl can effectively etch the oxidative layer and passivate the surface indium dangling bonds in the form of atomic ligands. The proposed charge carrier recombination model suggests that the significantly improved PL QY after acid treatment is attributed to the recombination of electron-hole pairs mainly from the conduction band and valence band. InP QDs treated with HF exhibit the best luminescence properties, with a high PL QY of 96%, offering great potential for advanced optoelectronic devices.
JOURNAL OF LUMINESCENCE
(2023)
Article
Chemistry, Multidisciplinary
Zhihang Long, Xin Tong, Rui Wang, Ali Imran Channa, Xin Li, Yimin You, Li Xia, Mengke Cai, Hongyang Zhao, Zhiming M. Wang
Summary: In this study, environmentally friendly AISe/ZnSe core/shell QDs were successfully synthesized and it was demonstrated that adjusting the shell thickness can improve the performance of the photoelectrochemical device, suggesting their potential application in solar energy conversion.
Article
Chemistry, Physical
Xin Li, Xin Tong, Shuai Yue, Cheng Liu, Ali Imran Channa, Yimin You, Rui Wang, Zhihang Long, Zheming Zhang, Zhenhuan Zhao, Xin-Feng Liu, Zhiming M. Wang
Summary: This study demonstrates the growth of multifunctional AgGaS2/CdSeS core/shell quantum dots with enhanced visible light absorption, red-shifted emission and prolonged exciton lifetime using a simple two-step synthetic method. The heterostructured core/shell quantum dots show improved charge separation/transfer properties, leading to efficient solar energy conversion and light detection in photoelectrochemical cells and photodetectors. These findings suggest the promising potential of rational design of core/shell architecture for versatile and high-performance optoelectronic applications.
Article
Chemistry, Physical
Andrei Mitrofanov, Anatol Prudnikau, Francesco Di Stasio, Nelli Weiss, Rene Huebner, Anna Maria Dominic, Konstantin B. L. Borchert, Vladimir Lesnyak, Alexander Eychmueller
Summary: This study successfully synthesized core/shell NPLs containing 0D CdxHg1-xSe domains in CdSe NPLs, and coated them with a CdyZn1-yS shell while preserving their 2D morphology. The NPLs exhibit bright photoluminescence in the near-infrared range with high quantum yields, making them a promising material for light-emitting applications.
CHEMISTRY OF MATERIALS
(2021)
Article
Chemistry, Physical
Lemma Teshome Tufa, Van Tan Tran, Ki-Jae Jeong, Birhanu Bayissa Gicha, Bedasa Abdisa Gonfa, Jaebeom Lee
Summary: Porous core-shell nanoparticles are a promising material with various applications. This study used cyclic voltammetry to reveal the porosity of core-shell nanoparticles and quantitatively determine the ratio of porous and nonporous structures.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Inorganic & Nuclear
Junzi Li, Zhihang Guo, Shuyu Xiao, Yudi Tu, Tingchao He, Wenjing Zhang
Summary: In this study, we synthesized core/shell hybrid perovskite nanocrystals with optimized optical stability and enhanced two-photon absorption, making them promising for application in nonlinear optoelectronic devices.
INORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Physical
Lei Jin, Jiabin Liu, Xin Liu, Daniele Benetti, Gurpreet Singh Selopal, Xin Tong, Ehsan Hamzehpoor, Faying Li, Dmytro F. Perepichka, Zhiming M. Wang, Federico Rosei
Summary: Thick-shell colloidal quantum dots (QDs) with size/composition/shape-tunable properties are promising for solar technologies. However, the commonly used toxic metal elements and wide bandgap of the shell limit their performance. This study develops eco-friendly AgInSe2/AgInS2 core/shell QDs, which are optically active in the NIR region and suitable for solar energy conversion. By using a template-assisted cation exchange method, gradient AgInSeS shell layers are incorporated, resulting in improved charge transfer and higher current density in the photoelectrochemical cells.
Article
Chemistry, Physical
Byeong Guk Jeong, Jun Hyuk Chang, Donghyo Hahm, Seunghyun Rhee, Myeongjin Park, Sooho Lee, Youngdu Kim, Doyoon Shin, Jeong Woo Park, Changhee Lee, Doh C. Lee, Kyoungwon Park, Euyheon Hwang, Wan Ki Bae
Summary: This study presents an approach to control the potential profile of III-V-II-VI h-NCs by steering dipole densities at the interface, allowing for control of the optical and electrical characteristics of these heterostructured nanocrystals. The synthesis of h-NCs with atomic precision enables correlation of interfacial dipole moments with the crystals' photochemical stability and optoelectronic performance. Controlled synthesis of heterostructured III-V-II-VI nanocrystals demonstrates that dipole moments formed at the core-shell interface can tune the optoelectronic properties of these nanomaterials and their performance in light-emitting devices.
Article
Materials Science, Multidisciplinary
Bathula Babu, Sunil Babu Eadi, Jihyung Yoo, Hi-Deok Lee, Kisoo Yoo
Summary: A novel composite supercapacitor electrode material, ZnWO4 nanorods decorated with colloidal SnO2 quantum dots, was synthesized via a facile sonochemical method. The successful construction of core@shell nanorods was confirmed through systematic characterization. SnO2 surface encapsulation on ZnWO4 nanorods improves electrochemical performance by enhancing conductivity and adding storage sites. The synthesized material displayed a specific capacitance of 162 F/g and 98% capacity retention after 5000 cycles.
Article
Optics
Xia Ran, Congcong Chen, Zhongran Wei, Zhen Chi, Yatao Pan, Yanmin Kuang, Xiaojuan Wang, Lijun Guo
Summary: This study investigates the shell-dependent blinking behavior and carrier dynamics in CdxZn1-xSeyS1-y@ZnS core/shell quantum dots. The results show that the on-time fraction of blinking emission can be effectively increased by capping the ZnS shell, and the carrier dynamics exhibit dependence on the shell thickness. These findings demonstrate the importance of shell encapsulation in regulating the optical properties of quantum dots.
JOURNAL OF LUMINESCENCE
(2022)
Article
Chemistry, Physical
Jiajia Ning, Yuan Xiong, Stephen Kershaw, Andrey L. Rogach
Summary: The most efficient way to improve the stability and optical properties of nanocrystals is to grow shell around their cores. Different growth modes of the ZnS shell on ZnSe nanorods were observed depending on the crystal structure of the ZnSe core, leading to differences in photoluminescence quantum yield.
CHEMISTRY OF MATERIALS
(2021)
Article
Chemistry, Inorganic & Nuclear
Xinyuan Li, Mengyao Su, Yi-Chi Wang, Meng Xu, Minman Tong, Sarah J. Haigh, Jiatao Zhang
Summary: This study developed an efficient strategy to synthesize telluride core-shell colloidal semiconductor nanoparticles (CSNPs) with thin amorphous shells using aqueous cation exchange (ACE). The crystallinity and shell thickness of the CSNPs could be controlled by changing the synthesis temperature. The CSNPs synthesized at 60 degrees C exhibited the highest surface-enhanced Raman scattering activity.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Rashid A. Ganeev, Andrey Zvyagin, Ivan A. Shuklov, Maksim G. Spirin, Oleg Ovchinnikov, Vladimir F. Razumov
Summary: InP@ZnS core-shell colloidal quantum dots were synthesized and characterized, with their nonlinear refraction and absorption coefficients determined using the z-scan technique. The study found saturable absorption and reverse saturable absorption phenomena in these CQDs, and demonstrated optical limiting effects within a certain intensity range. The research also discussed the thermal nature of negative nonlinear refraction in the studied species.
Article
Multidisciplinary Sciences
Niclas S. Mueller, Yu Okamura, Bruno G. M. Vieira, Sabrina Juergensen, Holger Lange, Eduardo B. Barros, Florian Schulz, Stephanie Reich
Article
Multidisciplinary Sciences
Florian Schulz, Ondrej Pavelka, Felix Lehmkuehler, Fabian Westermeier, Yu Okamura, Niclas S. Mueller, Stephanie Reich, Holger Lange
NATURE COMMUNICATIONS
(2020)
Article
Chemistry, Physical
Holger Lange, David F. Kelley
JOURNAL OF PHYSICAL CHEMISTRY C
(2020)
Article
Chemistry, Multidisciplinary
Florian Schulz, Fabian Westermeier, Francesco Dallari, Verena Markmann, Holger Lange, Gerhard Gruebel, Felix Lehmkuehler
ADVANCED MATERIALS INTERFACES
(2020)
Article
Optics
Kartik Ayyer, P. Lourdu Xavier, Johan Bielecki, Zhou Shen, Benedikt J. Daurer, Amit K. Samanta, Salah Awel, Richard Bean, Anton Barty, Martin Bergemann, 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 Lubke, Thomas Michelat, Andrew J. Morgan, Nils Roth, Tokushi Sato, Margin Sikorski, Florian Schulz, John C. H. Spence, Patrik Vagovic, Tamme Wollweber, Lena Worbs, Oleksandr Yefanov, Yulong Zhuang, Filipe R. N. C. Maia, Daniel A. Horke, Jochen Kuepper, N. Duane Loh, Adrian P. Mancuso, Henry N. Chapman
Summary: Single particle imaging at XFELs has the potential to determine the structure and dynamics of single biomolecules at room temperature. By overcoming hurdles in collecting high-quality diffraction patterns and computational purification, researchers have successfully obtained sub-nano meter resolution 3D reconstructions for biomolecular imaging. These advancements in X-ray sources, detectors, sample delivery, and data analysis algorithms illuminate new possibilities for characterizing diverse ensembles at the structural level.
Article
Chemistry, Multidisciplinary
Niclas S. Mueller, Emanuel Pfitzner, Yu Okamura, Georgy Gordeev, Patryk Kusch, Holger Lange, Joachim Heberle, Florian Schulz, Stephanie Reich
Summary: Research shows that plasmonic supercrystals, with a high density of hotspots, are an excellent platform for enhancing vibrational spectra by increasing the cross section of Raman scattering and infrared absorption. The study demonstrates that the intensity of surface-enhanced Raman scattering inside the crystal is uniform and predictable, with supercrystal polaritons inducing resonances in the enhanced cross section for both Raman scattering and infrared absorption. The enhancement of infrared absorption within supercrystals is attributed to the combined effects of hotspot formation and the excitation of standing polariton waves.
Article
Nanoscience & Nanotechnology
Yannic U. Staechelin, Dominik Hoeing, Florian Schulz, Holger Lange
Summary: Hot electrons in metal nanoparticles thermalize with the lattice via electron-phonon coupling, and this process is influenced by the particle's crystalline structure and size. Size dependency is not observed in polycrystalline particles, while monocrystalline particles exhibit a size-dependent electron-phonon coupling, with larger particles showing slower coupling due to decreased electron-surface scattering effects.
Article
Chemistry, Physical
Yannic U. Staechelin, Michael Deffner, Sonja Krohn, Christian Castillo Delgadillo, Jan Steffen Niehaus, Holger Lange
Summary: By optical and THz pump-probe spectroscopy, we find that only shell-located electrons in quantum rods contribute to photoconductivity, while core-located carriers form immobile excitons that respond to external electrical fields.
JOURNAL OF CHEMICAL PHYSICS
(2022)
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
Hannes Van Avermaet, Pieter Schiettecatte, Sandra Hinz, Luca Giordano, Fabio Ferrari, Celine Nayral, Fabien Delpech, Janina Maultzsch, Holger Lange, Zeger Hens
Summary: This study presents a synthesis protocol for forming InP-based quantum dots with high quantum efficiency across the full visible spectrum. By introducing specific interfacial treatments and a core/shell/shell structure, the researchers achieved the intended emission color while minimizing line broadening caused by lattice mismatch. The realization of this high quantum efficiency in full-spectrum color conversion will greatly facilitate research into light-matter interaction.
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, Physical
Robert Salzwedel, Andreas Knorr, Dominik Hoeing, Holger Lange, Malte Selig
Summary: We present a microscopic approach to understand the beginning of radial oscillation in silver nanoparticles. Using the Heisenberg equation of motion framework, we demonstrate that the coupled dynamics of coherent electron occupation and coherent phonon amplitude induce periodic size oscillations in the nanoparticle. Our results suggest a more direct coupling mechanism between field intensity and coherent phonons, which triggers size oscillations via optically induced electron density gradient. This mechanism is more efficient than the incoherent heating process commonly discussed in literature and provides a better explanation for the early onset of oscillations observed in recent experiments.
JOURNAL OF CHEMICAL PHYSICS
(2023)
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.
Article
Optics
Yannic U. Staechelin, Tobias Kroh, Franz X. Kaertner, Holger Lange
Summary: Optical-pump-terahertz-probe (OPTP) experiments are commonly used to study the behaviors of excited carriers in semiconductors. However, the size difference between the probe beam and the pump beam can cause distortions in the sample response and uncertainties in calculated conductivities and models. By investigating the influence of pump beam spot size and evaluating model calculations, we show the impact of this effect on the acquired data and provide guidelines for optimal experimental configurations.
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS
(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.
