近日，广东工业大学的刘伯梅及其研究小组与中山大学的王静等人合作并取得一项新进展。经过不懈努力，他们实现单组分非化学计量型CaGa_xO₄:Bi的激发波长依赖性持续发光动态防伪。相关研究成果已于2024年10月10日在国际知名学术期刊《光：科学与应用》上发表。

本研究介绍了一种非化学计量比的化合物CaGa_xO₄:Bi（x<2），该材料展现出超长且颜色可调的持续发光特性。通过改变激发波长，可以实现对持续发光波长的调节，从而在可见光谱的绿色到橙色区域内实现动态色彩调制。

结合理论计算与实验观察，本研究揭示了各种缺陷态的热力学电荷转移过程，深入探讨了Bi³⁺发光中心、势阱与多色持续发光之间的关系。此外，还展示了颜色可调持续发光材料及其柔性装置在不可见紫外线视觉检测、多色显示、信息加密和防伪方面的应用潜力。这些发现为开发具有动态控制持续发光特性的智能光电材料，并应用于多个领域，开辟了新的机遇。

据悉，在显示、生物传感和信息安全等领域，对能在可见光谱范围内实现动态持续发光（PersL）的材料需求迫切。然而，能同时满足肉眼可识别且发光特性依赖于激发波长的持续发光材料十分罕见。

附：英文原文

Title: Excitation-wavelength-dependent persistent luminescence from single-component nonstoichiometric CaGa_xO₄:Bi for dynamic anti-counterfeiting

Author: Liu, Bo-Mei, Lin, Yue, Liu, Yingchun, Lou, Bibo, Ma, Chong-Geng, Zhang, Hui, Wang, Jing

Issue&Volume: 2024-10-10

Abstract: Materials capable of dynamic persistent luminescence (PersL) within the visible spectrum are highly sought after for applications in display, biosensing, and information security. However, PersL materials with eye-detectable and excitation-wavelength-dependent characteristics are rarely achieved. Herein, a nonstoichiometric compound CaGa_xO₄:Bi (x<2) is present, which demonstrates ultra-long, color-tunable PersL. The persistent emission wavelength can be tuned by varying the excitation wavelength, enabling dynamic color modulation from the green to the orange region within the visible spectrum. Theoretical calculations, in conjunction with experimental observations, are utilized to elucidate the thermodynamic charge transitions of various defect states, thereby providing insights into the relationship between Bi³⁺ emitters, traps, and multicolored PersL. Furthermore, the utility of color-tunable PersL materials and flexible devices is showcased for use in visual sensing of invisible ultraviolet light, multicolor display, information encryption, and anti-counterfeiting. These discoveries create new opportunities to develop smart photoelectric materials with dynamically controlled PersL for various applications.

DOI: 10.1038/s41377-024-01635-7

Source: https://www.nature.com/articles/s41377-024-01635-7