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335 results on '"Hua, Youjie"'

26. Preparation and Luminescence Properties of Broadband Orange-Emitting Persistent ScBaZn3GaO7:Bi3+Phosphor

Author

Liu, Shulian, Fu, Mingwei, Qiao, Peng, Li, Yingguang, Deng, Degang, Hua, Youjie, Xu, Shiqing, and Ma, Hongping

Abstract

This article describes a new kind of afterglow material, ScBaZn3GaO7:Bi3+, which was synthesized through a high-temperature solid-phase method. Its crystal structure, photoluminescent characteristics, and afterglow characteristics were studied and analyzed. Upon excitation at 344 nm, ScBaZn3GaO7:Bi3+exhibits broadband emission with a central wavelength located at 571 nm (fwhm = 172.98 nm). The sample exhibits an internal quantum efficiency of 65.1%. The bright yellow persistent luminescence of the ScBaZn3GaO7:Bi3+sample was observed after 365 nm irradiation. Thermoluminescence spectroscopy revealed four primary traps within ScBaZn3GaO7:Bi3+, with depths of 0.676, 0.794, 0.882, and 0.972 eV. The traps located at energy levels of 0.676 and 0.794 eV were identified as the key contributors to the sample’s afterglow. Finally, the ScBaZn3GaO7:Bi3+sample was combined with a UV-LED chip to fabricate a high-power warm white-light-emitting diode (WLED) device, indicating the potential application prospect of ScBaZn3GaO7:Bi3+phosphor in single-phase warm WLEDs.

Published
2024
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28. Tunable emission of Ce3+ in (K, Rb)3GdSi2O7 phosphors toward broadband cyan luminescence.

Author

Li, Jiawen, Huang, Feifei, Hua, Youjie, Li, Bingpeng, Xu, Shiqing, and Lei, Ruoshan

Subjects
LUMINESCENCE spectroscopy, PHOSPHORS, LUMINESCENCE, LIGHT emitting diodes, TERBIUM, DIPOLE-dipole interactions, INDUCTIVE effect, ALKALI metals
Abstract

In an effort to obtain a novel cyan‐emitting phosphor, the [K1‐xRbx]3GdSi2O7: yCe3+ materials (x = 0, 0.1, 0.2, 0.3, 0.4, y = 0, 0.005, 0.01, 0.02, 0.03, 0.04) are synthesized via a solid‐state reaction pathway, and their crystal structure and luminescence behaviors are studied systematically. The chemical substitution of Rb+ in the K+ sites can enlarge the K3GdSi2O7 host lattice and help to the blue‐shifting of emission band of Ce3+ ions due to the decreased crystal field splitting effect. It is also confirmed that the Ce3+ ions tend to enter [Gd1O6] and [Gd2O6] polyhedrons simultaneously. Consequently, the [K0.7Rb0.3]3GdSi2O7: Ce3+ phosphor yields a broadband cyan emission centered at 492 nm with the full width at half maximum (FWHM) of ∼115 nm upon 365 nm excitation. The optimal concentration of Ce3+ dopant is determined to be 0.01, and the concentration quenching effect can be attributed to the dipole−dipole interactions. The white light emitting diode (WLED) device fabricated by employing the discovered [K0.7Rb0.3]3GdSi2O7: 0.01Ce3+ phosphor displays a high color rendering index (Ra = 91.7) and a low correlated color temperature (CCT = 3749 K). This work may promote the development of cyan phosphors for near ultraviolet‐converted WLEDs with high performance. [ABSTRACT FROM AUTHOR]

Published
2024
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35. Lanthanide Nd ion-doped two-dimensional In2Se3 nanosheets with near-infrared luminescence property

Author

Liu Yuan, Bai Gongxun, Jiang Li, Hua Youjie, Chen Liang, and Xu Shiqing

Subjects
2d material, in2se3 nanosheets, lanthanide ions, near-infrared, luminescence property, Physics, QC1-999
Abstract

Ultrathin two-dimensional (2D) materials have drawn great attention in recent years due to their promising applications in biomedicine and atomically optoelectronic devices. In this work, we have fabricated a 2D In2Se3 nanosheet doped with Nd3+ ions via the two-step method of solid phase synthesis and liquid exfoliation. Owing to the special inner 4f-4f energy level transitions, lanthanide ions can emit photons with almost the same energy in different environments. Here, a stable near-infrared luminescence from Nd3+-doped 2D In2Se3 nanosheets has been realized, which includes emission bands around 910, 1057, and 1324 nm. The doping of Nd3+ ions extends the emission region of In2Se3 nanosheets. Moreover, the photoluminescence mechanism of Nd3+ ions was investigated through a series of optical measurements. This work not only provides a reliable method to fabricate lanthanide ion-doped 2D materials but also possesses a great significance for luminescence study of lanthanide ions in the 2D matrix.

Published
2020
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36. A new generation of dual-mode optical thermometry based on ZrO2:Eu3+ nanocrystals

Author

Zhou Jun, Lei Ruoshan, Wang Huanping, Hua Youjie, Li Denghao, Yang Qinghua, Deng Degang, and Xu Shiqing

Subjects
temperature sensing, valley-to-peak ratio, decay lifetime, nanocrystals, rare earth ion, Physics, QC1-999
Abstract

For achieving well-performing optical thermometry, a new type of dual-mode optical thermometer is explored based on the valley-to-peak ratio (VPR) and fluorescence lifetime of Eu3+ emissions in the ZrO2:Eu3+ nanocrystals with sizes down to 10 nm. In the VPR strategy, the intensity ratio between the valley (600 nm) generated by the emission band overlap and the 606 nm peak (5D0→7F2), which is highly temperature sensitive, is employed, giving the maximum relative sensing sensitivity (Sr) of 1.8% K−1 at 293 K and good anti-interference performance. Meanwhile, the 606 nm emission exhibits a temperature-dependent decay lifetime with the highest Sr of 0.33% K−1 at 573 K, which is due to the promoted nonradiative relaxation with temperature. These results provide useful information for constructing high-performance dual-mode optical thermometers, which may further stimulate the development of photosensitive nanomaterials for frontier applications.

Published
2019
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