Role of Er3+ concentration on the photoluminescence and temperature sensing properties in Er3+ doped Y2O3 based transparent ceramics

The photoluminescence and temperature sensing properties of Er3+ doped Y2O3 based transparent ceramics have been studied as a function of Er3+ doping concentration. The samples exhibit high transparency thanks to the homogeneous microstructure with no obvious impurities or pores. Under 980 nm excitation, strong visible upconversion (UC) and near infrared (NIR) emissions of Er3+ ions are observed. By using the fluorescent intensity ratio (FIR) technique, the temperature sensing properties are investigated based on the thermally coupled levels 2H11/2 and 4S3/2 (FIR-1 = I544/I569) and non-thermally coupled levels 4F9/2 and 4S3/2 (FIR-2 = I666/I569) of Er3+ ions, respectively. The Judd-Ofelt (J-O) theory analysis reveals that the local crystal field around Er3+ ion changes with the doping concentration, leading to the tuned absolute sensing sensitivity (Sa) based on FIR-1. As for FIR-2, the sensing sensitivities of the samples enhance with the increasing Er3+ content due to the promoted nonradiative processes (including 4S3/2 → 4F9/2 and 4F7/2 + 4I11/2 → 4F9/2 + 4F9/2). The optimal Sa reaches ~371.8 × 10−4 K−1 in 6 mol% Er3+ doped sample, ranking among the highest ones for the luminescent materials. [Display omitted] •A high transmittance of 76.3% is obtained in Er3+ ion doping Y2O3 ceramics.•Multi-parametric thermometry is achieved in Er3+ doped Y2O3 transparent ceramics.•Thermometric behavior affected by FIR type and Er3+ concentration is investigated.•The highest sensitivity is 371.8 × 10−4 K−1 based on non-TCLs of 4F9/2 and 4S3/2.•The researched transparent ceramics can serve as an excellent thermometric material.