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77. Long-wavelength near-infrared light emitting Ni2+-doped double perovskite molybdate-based solid-solution phosphors.

Author

Zhu, Fengmei, Gao, Yuan, and Qiu, Jianbei

Abstract

Long wavelength near-infrared (LWNIR) light (1000–2000 nm) has great potential in the field of biomedical imaging, non-visual illumination, and non-destructive detection. However, currently, such as Cr3+ and Ni2+ can achieve broadband NIR emission, but their emission wavelengths are under 1600 nm with limited tunability. Herein, we developed Ni2+-doped (Sr/Ba)2MgMoO6 double perovskite molybdate-based solid-solution LWNIR phosphors via the high-temperature solid-state method. By adjusting the ratio of Sr/Ba in the phosphors, NIR emission peaks can be tuned from 1400 nm to 1610 nm under 400 nm excitation. Based on the analysis of crystal structures and luminescence characteristics and simulation results, we propose that the main reason for the shift of NIR peak emission is the difference in charge density and symmetrical polarizability of Ni2+ ions in the center of the octahedron due to the crystal structural changes of the matrices from tetragonal Sr2MgMoO6 to cubic phase Ba2MgMoO6. We constructed a LWNIR pc-LED with the optimal phosphors and a commercially near-ultraviolet LED chip, which efficiently emitted LWNIR light. The utility of this new LWNIR pc-LED as the NIR light source for non-invasive imaging and non-destructive detection of biological and non-biological objects was demonstrated. [ABSTRACT FROM AUTHOR]

Published
2024
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81. Dual‐Functional X‐Ray Photochromic Phosphor: High‐Performance Detection and 3D Imaging.

Author

Bai, Xue, Xu, Zan, Zi, Yingzhu, Zhao, Heping, Zhu, Bokun, Feng, Rongbao, Cun, Yangke, Huang, Anjun, Liu, Yue, Li, Yuewei, Qiu, Jianbei, Song, Zhiguo, Langford, Steven J., Liao, Jiayan, and Yang, Zhengwen

Subjects
THREE-dimensional imaging, LUMINESCENCE, PHOTOLUMINESCENCE, PHOSPHORS, PHOTOCHROMISM
Abstract

This study explores the integration of X‐ray‐induced photochromism and photoluminescence in a single material, offering innovative multi‐mode applications in optical memory, anti‐counterfeiting, and X‐ray detection and imaging. The photochromic phosphor LiAlSi2O6:Sm3+ is synthesized, which undergoes a color change from white to dark green under bright field conditions and displays orange photoluminescence in dark field conditions after X‐ray exposure due to defect formation. The phosphor shows accelerated bleaching and recovery under 473 nm laser stimulation. The distinct X‐ray‐induced color contrast and luminescence intensity modification in LiAlSi2O6:Sm3+ highlight its potential in advanced luminescent material design. Moreover, a LiAlSi2O6:Sm3+‐based flexible film demonstrates "dual‐mode" 3D X‐ray imaging and detection capabilities, paving the way for future X‐ray detecting and imaging device research. [ABSTRACT FROM AUTHOR]

Published
2024
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82. NIR regeneration and visible luminescence modification in photochromic glass: A novel encryption and 3D optical storage medium.

Author

Zhao, Heping, Li, Yuewei, Mi, Chao, Zi, Yingzhu, Bai, Xue, Haider, Asif Ali, Cun, Yangke, Huang, Anjun, Liu, Yue, Qiu, Jianbei, Song, Zhiguo, Liao, Jiayan, Zhou, Ji, and Yang, Zhengwen

Subjects
VISIBLE spectra, BINOCULARS, OPTICAL communications, DATA warehousing, LUMINESCENCE, PHOTOCHROMIC materials
Abstract

Photochromic glass shows great promise for 3D optical information encryption and storage applications. The formation of Ag nanoclusters by light irradiation has been a significant development in the field of photochromic glass research. However, extending this approach to other metal nanoclusters remains a challenge. In this study, we present a pioneering method for crafting photochromic glass with reliably adjustable dual‐mode luminescence in both the NIR and visible spectra. This was achieved by leveraging bimetallic clusters of bismuth, resulting in a distinct and novel photochromic glass. When rare‐earth‐doped, bismuth‐based glass is irradiated with a 473 nm laser, and it undergoes a color transformation from yellow to red, accompanied by visible and broad NIR luminescence. This phenomenon is attributed to the formation of laser‐induced (Bi+, Bi0) nanoclusters. We achieved reversible manipulation of the NIR luminescence of these nanoclusters and visible rare‐earth luminescence by alternating exposure to a 473 nm laser and thermal stimulation. Information patterns can be inscribed and erased on a glass surface or in 3D space, and the readout is enabled by modulating visible and NIR luminescence. This study introduces a pioneering strategy for designing photochromic glasses with extensive NIR luminescence and significant potential for applications in high‐capacity information encryption, optical data storage, optical communication, and NIR imaging. The exploration of bimetallic cluster formation in Bi represents a vital contribution to the advancement of multifunctional glass systems with augmented optical functionalities and versatile applications. [ABSTRACT FROM AUTHOR]

Published
2024
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98. Fine-Tuning Self-Trapped Excitons via External Coordination of Perovskite Octahedra: Simultaneous Achievement of Significant Stokes Shifts and Enhanced Emission

Author

Xu, Yusheng, Yang, Ruijing, Duan, Qiudong, Hong, Dongfeng, Zhou, Dacheng, Yang, Yong, Wen, Yugeng, Yang, Zhengwen, Wang, Qi, and Qiu, Jianbei

Abstract

Two zero-dimensional Sb-doped bismuth-based halide perovskites, Sb-doped Cs3BiCl6and Cs4BiCl7, were synthesized, and an in-depth analysis was conducted to elucidate the connection between lattice structure and self-trapped excitons (STE) properties. These perovskites introduced impurity energy levels in the valence band, enhancing electronic transitions and improving STE emission. Notably, Sb-doped Cs4BiCl7, an innovative material, exhibited higher photoluminescence (PL) intensity and a red shift in PL. The primary difference between these materials was the octahedral coordination environment, given their consistent elemental composition, octahedral dimensionality, and synthesis method. Cs4BiCl7’s looser atomic arrangement resulted in stronger phonon–electron coupling compared to Cs3BiCl6. Additionally, nonoctahedral chlorine in Cs4BiCl7increased electron occupation density in the conduction band, leading to a larger Stokes shift and more efficient electronic transitions. This study underscores the impact of the octahedral coordination environment on PL properties through detailed local structural analysis.

Published
2024
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99. Cr3+-Doped LiAlO2NIR-I Emitting Phosphors with Superior Resistance to Thermal Quenching for Night Vision Monitoring and Bioimaging

Author

Zhu, Fengmei, Gao, Yuan, and Qiu, Jianbei

Abstract

Near-infrared phosphor-converted light-emitting diodes (NIR pc-LEDs) as a new NIR light source has outstanding application potential in the fields of NIR spectroscopy analysis, sensing, imaging, and pattern recognition. Therefore, the development of NIR phosphors with good NIR luminescence thermal stability has attracted much attention. To this end, we developed LiAlO2:Cr3+garnet-type NIR phosphors by a high-temperature solid-state reaction method. Under 405 nm excitation, the Cr3+ions located in tetrahedrons of LiAlO2emit NIR emission in a broadband NIR emission that covers 650–900 nm mixed with several sharp narrowband R-line emissions, which showed excellent luminescence thermal stability with integrated intensity of emission measured at 573 K is ∼90.86% of that measured at 303 K caused by good structural rigidity and low thermal expansion coefficient of the matrix material. An NIR pc-LED device assembled with the optimized LiAlO2:Cr3+and a commercially available purple LED chip emitted NIR output power of ∼98.172 mW at a driving current of 300 mA and demonstrated an electro-optical conversion efficiency of ∼9.09%, while demonstrated it has excellent application potential in the fields of night vision monitoring and biomedical imaging.

Published
2024
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100. Ultrabroadband Long-Wavelength Near-Infrared MgIn2O4:Ni2+Phosphor Synthesized via Sol–gel Combustion Method as a Light Source for Night Vision Imaging, Nonvisual Detection, and Anticounterfeiting Display

Author

Deng, Yu, Zhu, Fengmei, Qiu, Jianbei, and Gao, Yuan

Abstract

Long-wavelength near-infrared (LWNIR) imaging technology has exciting application potential across various fields due to its ability of deeper penetration and unique properties related to its emission wavelength, when compared to short-wavelength near-infrared imaging. However, the limited availability of materials for LWNIR light sources, due to the lack of suitable host materials that constitute luminescence centers, has been a major challenge and technical obstacle in realizing such applications. Here, we developed MgIn2O4:Ni2+phosphors with an antispinel structure and LWNIR luminescence properties through a sol–gel combustion method. Under excitation at 365 nm, its emission wavelength covers the range of 1000–2000 nm, with a peak emission at approximately 1520 nm, a full width at half-maximum of ∼340 nm, and an optimized photoluminescence quantum yield of ∼21.22%, when an optimal Ni2+doping content of 1 mol % was used. Studies on the crystal structure of MgIn2O4have shown that Ni2+ions preferentially replace the lattice position occupied by Mg2+ions in the [MgO6] octahedrons, which provides a crystal field microenvironment of weak strength to the Ni2+luminescence centers and promotes their LWNIR emission with a large Stokes shift. A LWNIR pc-LED device was assembled using the optimized MgIn2O4:Ni2+phosphor and a near-ultraviolet LED chip (@ 365 nm), and its potential applications, including NIR night vision imaging, nonvisual detection, and anticounterfeiting displays, were demonstrated. Our results show that the antispinel MgIn2O4:Ni2+phosphor prepared by the sol–gel combustion method is a promising LWNIR luminescence material.

Published
2024
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