Guangjin Ou,Hongqing Song,Xinyong Gong,Ruirui Cui,Chaoyong Deng
A new green luminescent phosphor, Li(Y 1- x Tb x )GeO 4 , was prepared using a high-temperature solid-phase method. The X-ray diffraction (XRD) measured spectrum agreed well with the standard card JCPDS No. 02-3479, indicating that it is a quaternary compound belonging to the space group of Pnma(62) with an orthogonal crystalline phase; the excitation and emission spectra measured using the phosphor spectrometer showed that it can be effectively excited by near-ultraviolet light at 378 nm and blue light at 482 nm, and produced excellent strong emission of green light at 550 nm. The afterglow test results show that the sample had a good long afterglow effect at lower doping concentrations; the thermal stability test results showed that its thermal burst activation energy ΔE ≈ 0.37 eV had its excellent thermal stability. The rare earth Tb 3+ -doped green phosphor, LiYGeO 4 :Tb 3+ , has potential applications in household lighting, medical therapy, and optical storage.
Peishan Shao,Puxian Xiong,Dongliang Jiang,Zhicong Chen,Yao Xiao,Yongsheng Sun,Dongdan Chen,Zhongmin Yang
Mechanoluminescence (ML) materials, which can emit light under external mechanical stimuli, have attracted wide attention in diverse applications such as displays, anti-counterfeiting and 3D signatures. However, weak ML intensity and limited ML regulation methods are still limiting the development of ML materials. In this study, a series of Li0.997YGeO4:0.5% Bi3+,xTb3+ samples are synthesized by a high temperature solid-state reaction method. Based on photoluminescence (PL), crystal structures, ML, persistent luminescence (PersL), diffuse reflectance (DR) spectra and thermoluminescence (TL) analysis, the inherent relationship between PL, PersL and ML is further clarified in detail. The existence of abundant trap sites created by the vacancy of Li+ ions and the Bi3+ → Tb3+ energy transfer can improve the ML properties of phosphors. These excellent materials can open up a new approach for enhancing the ML intensity and expand the application of ML materials in the anti-counterfeiting fields.
Ying Lv,Ning Zhao,Chaofeng Li,Cunjian Lin,Shihai You
Efficient and stable persistent phosphors play a crucial role in the fields of energy storage, anti-counterfeiting, and biomedical fields. Here, we present an improved synthetic method for preparing a series of color-tunable LiYGeO 4 :Tb 3+ persistent phosphor. The increased Tb 3+ concentration in the improved method enhances the persistent luminescent intensity at 20 s by ∼2.96 times. This enhancement is due to the dual roles of Tb 3+ as both emitters and trap centers within LiYGeO 4 . By simply increasing the doping concentrations, the persistent color can be adjusted from blue to green. LiYGeO 4 :Tb 3+ exhibits no loss of persistent luminescent intensity even after exposure to water at 80 °C for 72 h, surpassing the commercial green persistent phosphor. Furthermore, information storage was successful demonstrated by using LiYGeO 4 :Tb 3+ with various doping concentrations. This study represents a significant advancement in optimizing the properties of persistent luminescent materials, where dopants simultaneously serve as emitters and trap centers.
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