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852 results on '"Chen, Junsheng"'

62. Blue Long Afterglow and Ultra Broadband Vis‐NIR Emission from All‐Inorganic Copper‐Doped Silver Halide Single Crystals.

Author

Wang, Sijia, Liu, Runze, Li, Juntao, Meng, Caixia, Liu, Jianyong, Chen, Junsheng, Cheng, Pengfei, and Wu, Kaifeng

Subjects
SILVER halides, SINGLE crystals, DOPING agents (Chemistry), COPPER, PHOTONS, METAL halides
Abstract

All‐inorganic metal halides with afterglow emission have attracted increasing attention due to their significantly longer afterglow duration and higher stability compared to their organic–inorganic hybrid counterparts. However, their afterglow colors have not yet reached the blue spectral region. Here, we report all‐inorganic copper‐doped Rb2AgBr3 single crystals with ultralong blue afterglow (>300 s) by modulating defect states through doping engineering. The introduction of copper(I) ions into Rb2AgBr3 facilitates the formation of bromine vacancies, thus increasing the density of trap states available for charge storage and enabling bright, persistent emission after ceasing the excitation. Moreover, cascade energy transfer between distinct emissive centers in the crystals results in ultra‐broadband photoluminescence, not only covering the whole white light with near‐unity quantum yield but also extending into the near‐infrared region. This 'cocktail' of exotic light‐emission properties, in conjunction with the excellent stability of copper‐doped Rb2AgBr3 crystals, allowed us to demonstrate their implementation to solid‐state lighting, night vision, and intelligent anti‐counterfeiting. [ABSTRACT FROM AUTHOR]

Published
2024
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64. B(I)‐Site Alkali Metal Engineering of Lead‐Free Perovskite Nanocrystals for Efficient X‐Ray Detection and Imaging.

Author

Wang, Zhongyi, Chen, Junsheng, Xu, Xin, Bai, Tianxin, Kong, Qingkun, Yin, Hong, Yang, Yang, Yu, William W., Zhang, Ruiling, Liu, Xiaojing, and Han, Keli

Subjects
*X-ray detection, *ALKALI metals, *X-ray imaging, *PEROVSKITE, *EXCITON-phonon interactions, *SCINTILLATORS, *FEMTOSECOND pulses
Abstract

Lead‐free metal halide double perovskites have emerged as promising scintillators owing to their superior optoelectronic properties, low‐cost and solution processability. However, it is still challenging to develop high‐performance flexible X‐ray scintillators based on the B(I)‐site alkali metal modulation in lead‐free double perovskite nanocrystals (NCs). Herein, a series of novel Cs2B(I)GdCl6 (B: Li, Na, K) of double perovskite A2B(I)M(III)X6 NCs structures are successfully synthesized, the optical and scintillator properties of which are significantly sensitive to the B(I)‐site alkali metals with the doping of Sb3+. They showed efficient self‐trapped exciton (STE) emission with high photoluminescence quantum yield (PLQY) and exhibited the highest X‐ray detection limit (86 nGyair s−1) and excellent spatial resolutions (>15 lp mm−1). The femtosecond transient absorption measurement and theoretical analysis further revealed that the B(I)‐site alkali metal fundamentally balanced the exciton–phonon coupling with appropriate STEs formation energy barrier and the electron localization and thus improved the optical and scintillator properties. This B(I)‐site alkali metal engineering offers a strategy to develop bright luminescent double perovskite NCs for X‐ray detection and imaging devices. [ABSTRACT FROM AUTHOR]

Published
2024
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95. Facile synthesis of defect-rich Fe-N-C hybrid from fullerene/ferrotetraphenylporphyrin as efficient oxygen reduction electrocatalyst for Zn-air battery

Author

Wang, Hai, primary, Cao, Liyun, additional, Feng, Yongqiang, additional, Chen, Junsheng, additional, Feng, Weihang, additional, Luo, Tianmi, additional, Hu, Yuzhu, additional, Yuan, Chengke, additional, Zhao, Yajuan, additional, Zhao, Yong, additional, Kajiyoshi, Koji, additional, Liu, Yijun, additional, Li, Zhenjiang, additional, and Huang, Jianfeng, additional

Published
2023
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99. An Array Sensor Measurement Method for Easily Confused Gases (CO, H<inf>2</inf>, CH<inf>4</inf>) in the Field Based on Cross-Talk Characteristics

Author

Jiang, Tianyan, Tan, Sirun, Yuan, Haoxiang, Chen, Xi, Bi, Maoqiang, and Chen, Junsheng

Abstract

The three gases CO, H2, and CH4 are currently prevalent in various industrial environments, posing a threat to life and property. However, the crosstalk phenomenon between the gas mixtures cannot be avoided by technological improvement in practical measurements. To adapt to field measurement requirements, this paper experimentally investigates the crosstalk characteristics of mixed gases and proposes a measurement method based on the cross-talk characteristics of field-confusable gas array sensors. The experimental results show that compared with the traditional direct measurement method, the proposed method reduces the crosstalk error from 50.1% to 10.3%, which significantly improves the accuracy of the field detection. At the same time, the method is not limited by the sensor category, which is applicable to the field measurement of various types of array sensors.

Published
2024
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100. Towards High-Power and -Efficiency ∼2.8 μm Lasing: Lightly-Erbium-Doped ZrF4 Fiber Laser Pumped at ∼1.7 μm

Author

Luo, Hongyu, Shi, Junchuan, Chen, Junsheng, Wang, Yongzhi, Li, Jianfeng, Wu, Han, and Liu, Yong

Abstract

In this article, we demonstrate great potential of lightly-erbium(Er3+)-doped ZrF4 fiber in efficient power scaling at ∼2.8 μm, when excited at ∼1.7 μm. Core-pumped by a random Raman fiber laser at 1.69 μm, the 1.5 mol.% Er3+-doped ZrF4 fiber in a F-P cavity has experimentally yielded an output power of >6 W at 2.783 μm with a slope efficiency of up to 58.4% (with respect to the absorbed pump), close to its Stokes limit of 60.7% (1.69/2.783). To our knowledge, this is the highest efficiency of Er3+-doped ZrF4 fiber lasers in the mid-infrared. Further power scaling is only limited by the current pump power. Based on the validated numerical model, the dominant role of the excited state absorption (ESA) process (i.e., $^4{\mathrm{I}}_{13/2}{ \to }^4{\mathrm{I}}_{9/2}$) in exciting efficient ∼2.8 μm laser has been highlighted, and the resonant ground state absorption process (i.e., $^4{\mathrm{I}}_{15/2}{ \to }^4{\mathrm{I}}_{13/2}$) is also essential. The simulation results indicate that the pump wavelength closer to the ESA peak can yield a higher slope efficiency. In addition, heat load analyses via numerical modeling reveals that the $^4{\mathrm{I}}_{9/2}{ \to }^4{\mathrm{I}}_{11/2}$ multiphonon relaxation is the main heat source of the system. By taking fiber optical damage limit into account simultaneously, a high-power lightly-Er3+-doped ZrF4 fiber laser arrangement has been proposed, which theoretically enables 100-W-class output under a slope efficiency of >50% and a relatively low heat load.

Published
2024
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