Bimolybdate single crystals codoping with trivalent ytterbium and erbium ions for high-stable and high-sensitive optical thermometry

• Published in: Journal of alloys and compounds 2024-10, Vol.1003, p.175767, Article 175767
• Main Authors: Wang, Miaomiao, Ding, Shoujun, Hu, Haitang, Zhang, Chuancheng, Ren, Hao, Zou, Yong, Liu, Wenpeng
• Format: Article
• Language: English
• Subjects: Czochralski method; Fluorescence intensity ratio; NaBi(MoO4)2 single crystal; Optical temperature sensing; Upconversion luminescence
• ISSN: 0925-8388
• DOI: 10.1016/j.jallcom.2024.175767

Replacing conventional powder polycrystalline materials with crystalline materials is an effective strategy to improve the sensing sensitivity, responsiveness, and anti-interference capabilities of the fluorescence intensity ratio (FIR) based optical temperature sensing techniques. In this work, Yb3+/Er3+ codoped bimolybdate single crystals, NaBi(MoO4)2 (NBM) with different Er3+ ion doping concentrations, were grown by the Czochralski method, in which is expected to be used for optical temperature sensing applications. The structure of the crystals was fully characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and transmission electron microscopy (TEM). Under 980 nm laser excitation, the crystals demonstrated notable green and slight red upconversion (UC) emissions, and the mechanism of UC luminescence was thoroughly investigated. The luminescence intensity was found to be contingent upon the doping concentration, which gradually decayed with increase of Er3+ ions. The optical temperature sensing performance of Yb3+/Er3+ codoped NBM single crystals was evaluated by the FIR technique based on the thermally coupled level of Er3+ ions (2H11/2/4S3/2). The experimental findings revealed that the 10 at% Yb3+, 10 at% Er3+: NBM crystal exhibited highest sensor sensitivity among the synthesized crystals, with a maximum absolute sensitivity of approximately 1.22 % K−1 at 510 K. Furthermore, the temperature sensing characteristics of the crystals appeared to be dependent on the doping concentration of Er3+ ions. In summary, the Yb3+/Er3+ codoped NBM single crystal showcased excellent sensor sensitivity and held considerable promise as materials for optical temperature sensing applications. •Bulk Yb3+/Er3+ codoped bimolybdate single crystals were grown for utilization in optical temperature sensing applications.•The optical temperature sensing properties of Yb3+/Er3+ codoped NBM single crystals were assessed utilizing the FIR technique.•The temperature sensing characteristics of the crystals were contingent upon the doping concentration of Er3+ ions.•A maximum absolute sensitivity of approximately 1.22 % K−1 at 510 K was achieved among the synthesized crystals.