Article
Chemistry, Physical
Zikun Tang, Yi Tao, Kanghong Wang, Dequan Bao, Zhenqiu Gao, Haiguang Zhao, Hao Zhang, Zhen Wen, Xuhui Sun
Summary: This study presents a unique synthetic approach to improve the transfer dynamics of photogenerated charges in heterostructured quantum dots (QDs) by incorporating metal ions (Mn2+) into the lattice during shell growth. The optimized QDs (Mn-0.03-CdSe/CdS) show a significantly higher saturated photocurrent density compared to undoped QDs (CdSe/CdS) under one sun illumination, attributed to the reduced conduction band offset and suppressed non-radiative recombination process of photogenerated charges introduced by Mn2+ ions. This work provides valuable guidance for enhancing the performance of optoelectronic devices based on heterostructured QDs.
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
Engineering, Electrical & Electronic
Ha Thanh Tung, Dang Huu Phuc
Summary: In this study, photovoltaic devices based on CdS/CdSe multilayer photoanodes were fabricated with Mn2+ ions doped into CdS or CdSe quantum dots. The optimal performance was achieved with a 30% Mn2+ doping concentration and a thickness of CdSe:Mn2+ film at 3 cycles, resulting in an efficiency of 3.9%.
OPTICAL AND QUANTUM ELECTRONICS
(2021)
Article
Chemistry, Multidisciplinary
Adi Harchol, Yahel Barak, Kira E. Hughes, Kimberly H. Hartstein, Huygen J. Jobsis, P. Tim Prins, Celso de Mello Donega, Daniel R. Gamelin, Efrat Lifshitz
Summary: This study elucidates the recombination processes and spin properties of copper-doped CdSe/CdS and CuInS2 colloidal quantum dots (CQDs) using optically detected magnetic resonance spectroscopy. The findings support different models for the magneto-optical properties of these important materials.
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
Nanoscience & Nanotechnology
Matteo Barelli, Cynthia Vidal, Sergio Fiorito, Alina Myslovska, Dimitrie Cielecki, Vincenzo Aglieri, Iwan Moreels, Riccardo Sapienza, Francesco Di Stasio
Summary: This study demonstrates the controlled placement of colloidal semiconductor nanocrystals onto planar surfaces by patterning nanohole arrays in a PMMA thin film and trapping the nanocrystals into the holes. The resulting arrays contain hundreds of single-photon emitters, providing a feasible, fast, and practical method for the fabrication of nanodevices based on colloidal semiconductor nanocrystals, such as single-photon-emitting LEDs.
Article
Chemistry, Multidisciplinary
Hui Zhang, Xiaohu Mi, Bowen Kang, Yunkai Wu, Tingting Zhang, Pai Liu, Xiaowei Sun, Zhenglong Zhang, Ning Liu, Hongxing Xu
Summary: Colloidal nanocrystals play a significant role in optoelectronic devices and their properties can be improved through ligand modification, which can enhance charge transport and emission characteristics in LEDs.
Article
Chemistry, Multidisciplinary
Hairui Lei, Tenghui Li, Jiongzhao Li, Jie Zhu, Haibing Zhang, Haiyan Qin, Xueqian Kong, Linjun Wang, Xiaogang Peng
Summary: This study investigates facet reconstruction of colloidal wurtzite CdSe/CdS core/shell nanocrystals under typical synthetic conditions and reveals that two sets of facets with specific low-index facets can be reversibly reconstructed by switching the ligand system, indicating their thermodynamic stability. The atomic structures of the low-index facets of wurtzite nanocrystals are diverse, and each facet is paired with a common ligand in the solution. The results suggest that facet-controlled nanocrystals can be synthesized by optimal facet-ligand pairing, enabling the formation of semiconductor nanocrystals with size-dependent properties at an atomic level.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Ying Tang, Qilin Qin, Hongyu Yang, Shengnan Feng, Chunfeng Zhang, Jiayu Zhang, Min Xiao, Xiaoyong Wang
Summary: This study demonstrates the ability to decrease the Auger decay and radiative rates in semiconductor nanocrystals by applying external electric fields. The decrease in the Auger rate is attributed to enhanced exciton-exciton repulsion, while the decrease in the radiative rate is attributed to weakened electron-hole exchange interaction. These findings highlight the potential of using external electric fields as a post-synthetic approach to manipulate the exciton recombination dynamics in semiconductor nanocrystals.
Article
Chemistry, Physical
Danja Fischli, Luisa Rieger, Klaus Boldt
Summary: Transition-metal-doped semiconductor nanocrystals have attracted interest in the field of spintronics. This paper presents a method for localized doping of CdSe/CdS dot-in-rods and investigates the interaction between dopants and excitons, as well as the kinetics of impurity diffusion.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Physical
Arun Ashokan, Paul Mulvaney
Summary: Solution-phase spectroelectrochemistry was used to study electron injection into colloidal CdSe quantum dots in THF. The results showed reversible optical changes on a time-scale of minutes, with the injection of electrons leading to quenching of photoluminescence. The number of electrons injected into the QDs depended on the electrode potential and QD size, with most injection occurring below the band edge.
CHEMISTRY OF MATERIALS
(2021)
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, Physical
Linxi Wang, Xudong Qian, Yang Ren, Hairui Lei, Xiaofei Hu, Dongdong Chen, Jiongzhao Li, Xiaogang Peng
Summary: In this study, CdS shells were grown epitaxially onto monodisperse zincblende CdSe core nanocrystals by varying the volume fraction of fatty amines in the epitaxy solution. The resulting core/shell nanocrystals showed unified shape and surface ligands, and the internal lattice defects could be controlled through surface treatments. The presence of twin faults and wurtzite CdS domains did not affect the electronic structure of the nanocrystals but had an impact on the photoluminescence decay dynamics.
CHEMISTRY OF MATERIALS
(2022)
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, Physical
Tom Galle, Daniel Spittel, Nelli Weiss, Volodymyr Shamraienko, Helena Decker, Maximilian Georgi, Rene Huebner, Nadia Metzkow, Christine Steinbach, Dana Schwarz, Vladimir Lesnyak, Alexander Eychmueller
Summary: The research transforms CdSe NPLs into PbSe NPLs suitable for optoelectronic applications through cation exchange, ligand exchange, and electronic coupling, successfully fabricating a photodetector with fast light response at low operational voltages on a commercial substrate.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)