Abstract Optical thermometry has drawn great attention due to its sensitive and noncontact properties. Herein, Yb3+/Er3+ codoped Bi4Ti3O12 phosphor microcrystals have been synthesized by solid phase reaction for optical temperature sensing. The phase, microscopic structure and morphology of the prepared sample have been studied by the X-ray diffraction, transmission electron microscopy, etc. The process of upconversion emission has been researched with different environmental temperature and excitation power under 980 nm laser excitation. Meanwhile, the temperature sensing nature of the as-prepared microcrystals has been investigated based on the luminescence intensity ratio of two thermally coupled energy levels (Er3+:2H11/2, 4S3/2). The excitation laser power density is 3.95 mW/mm2, and the absolute sensitivity reaches 0.0046 K-1. The result demonstrates potential of the Bi4Ti3O12:Yb3+/Er3+ microcrystals in making optical sensing device under low excitation power density.

中文翻译：

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基于 Yb3+/Er3+ 共掺杂钛酸铋微晶上转换发射的光学测温

摘要 光学测温因其灵敏、非接触的特性而备受关注。在此，通过固相反应合成了 Yb3+/Er3+ 共掺杂 Bi4Ti3O12 荧光粉微晶，用于光学温度传感。通过X射线衍射、透射电镜等手段研究了制备样品的物相、微观结构和形貌。研究了980 nm激光激发下不同环境温度和激发功率下的上转换发射过程。同时，基于两个热耦合能级 (Er3+:2H11/2, 4S3/2) 的发光强度比研究了所制备微晶的温度传感性质。激发激光功率密度为3.95 mW/mm2，绝对灵敏度达到0.0046 K-1。