Article
Optics
Haolin Li, Xuanyu Zhang, Haizhen Wang, Jiahao Yu, Kexue Li, Zhipeng Wei, Dehui Li, Rui Chen
Summary: This study characterizes the optical properties of self-trapped excitons (STEs) in two-dimensional perovskite materials using laser spectroscopy. It is found that STEs are related to octahedral distortion caused by strong electron-phonon interaction, and trapping and detrapping between STEs and free excitons (FEs) are observed. With increasing temperature, STEs and FEs migrate to each other. Additionally, the existence of STEs inside the material is confirmed through thickness-dependent and two-photon excitation emission.
PHOTONICS RESEARCH
(2022)
Article
Nanoscience & Nanotechnology
Qimiao Chen, Liyao Zhang, Yuxin Song, Xiren Chen, Sebastian Koelling, Zhenpu Zhang, Yaoyao Li, Paul M. Koenraad, Jun Shao, Chuan Seng Tan, Shumin Wang, Qian Gong
Summary: Highly tensile-strained Ge quantum dots emitting structures with different sizes were successfully grown on InP substrates by molecular beam epitaxy. The photoluminescence from direct band-gap-like transitions of TS-Ge-QDs was achieved, and the band structure of the TS-Ge-QDs emitting structures was calculated to support the experimental results. These results provide encouraging evidence for the future photonics applications of this promising highly tensile strained semiconductor-nanostructure-based platform such as integrated light sources.
ACS APPLIED NANO MATERIALS
(2021)
Article
Optics
Lei Wang, Lai Wang, Chien-Ju Chen, Kai-Chia Chen, Zhibiao Hao, Yi Luo, Changzheng Sun, Meng-Chyi Wu, Jiadong Yu, Yanjun Han, Bing Xiong, Jian Wang, Hongtao Li
Summary: In this study, InGaN quantum dots were proposed as the active region of micro-LEDs to address efficiency and bandwidth limitations. The results showed that utilizing InGaN QDs can provide a solution for higher efficiency and wider bandwidth micro-LEDs in display and VLC applications.
LASER & PHOTONICS REVIEWS
(2021)
Article
Physics, Applied
Xiaorui Wang, Tao Wang, Dapeng Yu, Shijie Xu
Summary: The article observes large negative thermal quenching of the yellow luminescence in non-polar InGaN/GaN quantum well samples when carriers are optically excited in the quantum well layers. A simple model considering the thermal transfer of carriers is proposed to interpret this phenomenon and the thermal activation energy of carriers is determined through data fitting.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Le Han, Yide Han, Junbiao Wu, Xia Zhang, Zhuopeng Wang, Yan Xu
Summary: The study presents a method to encapsulate CsPbX3 nanocrystals in a titanium silicate molecular sieve, forming stable nanocomposites with potential applications in temperature sensing and luminescent stability. The nanocomposites exhibit dual-mode temperature-readout properties and excellent stability in various polar solvents.
MATERIALS CHEMISTRY FRONTIERS
(2021)
Article
Chemistry, Multidisciplinary
Soumen Mukherjee, Swarnali Ghosh, Dibyendu Biswas, Mainak Ghosal, Kheyali De, Prasun K. Mandal
Summary: Zn-alloyed CsPb(Cl/Br)(3) perovskite nanocrystals (PNCs) were synthesized and used as a model system for Mn doping to study the effect of Mn doping on exciton dynamics. The radiative decay rate of the host band decreased by about 6.5 times and the non-radiative decay rate increased by about 2.5 times upon Mn doping, while keeping the PL emission maximum and PLQY of both PNC samples nearly the same. Unlike previous reports, the integrated PL intensity of the dopant emission in this case increased by about 5.5-fold when the temperature decreased from 290 K to 190 K. The presence of shallow trap states was responsible for the truncation in the PDDs of both ON and OFF events for PNC1, whereas the deep dopant states did not allow truncation in the host PL emission of PNC2.
Article
Nanoscience & Nanotechnology
H. Mohammadi, R. C. Roca, I Kamiya
Summary: Strain control and photoluminescence enhancement of InAs surface quantum dots have been achieved by introducing buried quantum dots. The study shows that strain and related effects dominate the electronic properties of the quantum dots, and buried quantum dots act as effective carrier reservoirs.
Article
Quantum Science & Technology
Qin Wan, Fei Zeng, Junwei Yu, Tongjin Chen, Ziao Lu, Feng Pan
Summary: Research and development of memristor-based neuromorphic networks has reached large-scale application stage, but a thorough understanding of the adopted memristors is still lacking. In this study, a method to manipulate the local activity of NbO quantum dot (QD) system by creating an electrode tip is proposed, enabling reversible nucleation behavior and periodic pulsing. These mechanisms contribute to the information-energy conversion in the QD system and provide a more precise and low energy-consumption approach for neuromorphic computing.
ADVANCED QUANTUM TECHNOLOGIES
(2023)
Article
Chemistry, Multidisciplinary
Xiaolei Chu, Alex Abelson, Caroline Qian, Oleg Igouchkine, Ethan Field, Kwan-Liu Ma, Matt Law, Adam J. J. Moule
Summary: Using scanning transmission electron microscopy (STEM) and full-tilt tomographic reconstruction, a single-crystalline region of a 3D epitaxially-fused PbSe quantum dot (QD) superlattice containing 633 QDs was imaged at a spatial resolution of 2.16 angstrom. The analysis revealed 3D mesoscale correlations of atomic lattice and superlattice order across hundreds of nanocrystals, and showed that the QD surface layers template the superlattice. The techniques presented in this study can be applied to a wide range of 3D nanostructured materials.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Biochemistry & Molecular Biology
Ilia Litvinov, Anna Salova, Nikolay Aksenov, Elena Kornilova, Tatiana Belyaeva
Summary: In this study, the photophysical characteristics of core/shell InP/ZnS quantum dots (InP-QDs) were analyzed in cell culture medium, salt solutions, and directly in the cells. It was found that InP-QDs were internalized into endolysosomes in HeLa and A549 cells with similar dynamics to Cd-based QDs, but the two cell lines accumulated them differently. InP-QDs were reliably detected in the endosomes despite their low quantum yields. Factors such as cell culture medium, acidic pH, and salt solutions were found to affect the photoluminescence lifetime of InP-QDs. The scatter between endosomes in the same cell was observed, indicating the complex impact of these factors on the state of InP-QDs. The toxicity of InP-QDs for both cell lines at concentrations higher than 20 nM was demonstrated.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Chemistry, Multidisciplinary
Mona Atabakhshi-Kashi, Monica Carril, Hossein Mahdavi, Wolfgang J. Parak, Carolina Carrillo-Carrion, Khosro Khajeh
Summary: The successful conjugation of antibodies onto a fluorescent NP assembly demonstrated that the NP assembly retained the targeting ability of the antibodies in cellular uptake, while also preserving its intrinsic properties such as fluorescence.
Article
Chemistry, Multidisciplinary
Ling Chen, Bowen Sheng, Shanshan Sheng, Ping Wang, Xiaoxiao Sun, Duo Li, Tao Wang, Renchun Tao, Shangfeng Liu, Zhaoying Chen, Weikun Ge, Bo Shen, Xinqiang Wang
Summary: This study demonstrates the room temperature triggered single photon emission from self-assembled GaN quantum dots embedded in AlN nanowires grown on Si (111) substrate. The GaN/AlN QDs exhibit strong emission in the range of 3.6-4.1 eV at 4.7 K, with a sharp emission width as narrow as 1.6 meV. The fast radiative lifetime and observable antibunching effect up to room temperature confirm the potential of practical quantum information applications.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
S. Yamamoto, R. Kaji, S. Adachi
Summary: In this study, the formation of the anomalous Hanle effect in a self-assembled quantum dot was investigated using experimental and theoretical approaches. The buildup time of the nuclear field was found to increase with increasing applied transverse magnetic field strength. Additionally, the inversion of the circular polarization degree of photoluminescence was observed to occur much faster than the buildup time of the nuclear field, indicating the importance of the in-plane component of the major principal axis of nuclear quadrupole interaction.
Article
Chemistry, Inorganic & Nuclear
Chuqiao Wu, Shuting Zhang, Yuhui Zheng, Aiqi Wang, Qiming Zhao, Wenjie Sun, Wanqiang Liu, Chenggang Long, Qianming Wang
Summary: In this article, a solvent-type passivation (STP) strategy is introduced to achieve better control and reproducibility of sulfur dots by using short-chain molecular species instead of polyethylene glycol (PEG) as the capping agent. The strategy does not require PEG or any other capping agent, and the surface defects of sulfur dots are passivated by sodium ethoxide generated through the direct reaction of ethanol with NaOH. The sulfur dots obtained through this strategy show self-quenching resistant feature in the solid state and an extended fluorescence band up to 645 nm.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Yuhao Ben, Feng Liang, Degang Zhao, Xiaowei Wang, Jing Yang, Zongshun Liu, Ping Chen
Summary: An anomalous increase in integrated photoluminescence intensity was observed in a GaN-based multiple quantum wells (MQWs) sample due to the involvement of non-equilibrium carriers and quantum barrier layers. The dynamics of non-equilibrium carriers between 100 to 140 K result in increased emission efficiency, with a much higher luminescence efficiency in MQWs with non-equilibrium carriers. The comparison analysis with and without hydrogen treatment further highlights the importance of a superior quantum well in this anomalous phenomenon.
