Optical thermometry and multi-mode anti-counterfeiting based on Bi3+/Ln3+ and Ln3+ doped Ca2ScSbO6 phosphors

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 481; p. 148717
• Main Authors: Zhang, Xibao, Xu, Yonghui, Wu, Xiudi, Yin, Shuwen, Zhong, Chuansheng, Wang, Chenxue, Zhou, Liang, You, Hongpeng
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.02.2024
• Subjects: Anti-counterfeiting; Energy transfer; Low-concentration quenching; Optical thermometry; Optical thermometry; Anti-counterfeiting; Energy transfer; Low-concentration quenching
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2024.148717

•The Ca2ScSbO6:Bi3+ phosphor exhibits efficient near-ultraviolet photoluminescence.•Low concentration quenching phenomenon was observed for Ca2ScSbO6:Eu3+ phosphor.•Optical thermometers were developed with wide temperature monitoring range and high sensitivity.•Multiple anti-counterfeiting modes were designed with a high level of security. A series of novel Bi3+/Ln3+-activated Ca2ScSbO6 (CSSO) phosphors were synthesized by solid-state method and their luminescent behaviors were investigated in detail. Under the 302 nm excitation, the CSSO:Bi3+ shows remarkable near-ultraviolet photoluminescence with a peak emission at 365 nm. Eu3+-activated CSSO phosphor possesses high efficiency and no obvious reduction of emission intensity even after replacing Sc with Eu completely, which indicates a low-concentration quenching effect. In addition, its emission intensity at 423 K (I423K) still maintains 88 % compared with that of at room temperature (I298K), indicating good thermostability. In contrast, the CSSO:Bi3+ phosphor exhibits a significant reduction in emission intensity, maintaining only 49 % of its luminescence at 423 K (I423K/I298K). By codoping Bi3+ and Ln3+ (Ln = Eu, Tb, Dy, Sm), the energy transfer was observed from the Bi3+ to Ln3+ ions, endowing the CSSO:Bi3+, Ln3+ phosphors with tunable multicolor emissions. Leveraging the differing thermostabilities of the emission spectra for Bi3+ and Ln3+ ions, we designed and assessed a range of sensitive optical thermometers. Among these, the CSSO:Bi3+, Eu3+ phosphors exhibited the best performance, boasting maximum absolute and relative sensitivities of 9.96 % K−1 and 2.002 % K−1, respectively. Additionally, we displayed the multi-mode anti-counterfeiting function of synthesized phosphors, and a multi-color switching system was designed with the advantages of direct visualization and easy identification of encrypted information. These results indicate that Bi3+ and Ln3+ coactivated CSSO phosphor has the potential application for non-contact temperature measurement and anti-counterfeiting.