We investigated the upconversion (UC) emissions and their ambient dependences of SrTiO₃ polycrystals co-doped in Er³⁺ and Yb³⁺ at different substitution sites. i.e., the A-site and B-sites in ABO₃-type perovskite, and its response to H₂ and O₂ ambient annealing. Under near-infrared excitation at 980 nm, the as-synthesized samples exhibited strong UC emission features in the green (525 and 550 nm) and red (660 nm) region from Er³⁺ ions owing to sensitization by Yb³⁺; the emission was much stronger for A-site doping than for B-site doping. Interestingly, annealing in the H₂ atmosphere to increase the oxygen vacancies suppressed the photoluminescence and UC emission of the A-site doped samples, but enhanced the emission signals of the B-site doped samples. After subsequent annealing in the O₂ atmosphere to decrease the oxygen vacancies, the emission intensities showed a tendency to return to those in the as-synthesized A-site doped and B-site doped samples. These intriguing behaviors were explained in terms of the relationship between the substitution site and charge compensation. We performed the temperature dependent UC emissions and found that the intensity ratio between two green emissions changed significantly with temperature. This strong fluorescence intensity ratio could be used for optical thermometry.

我们研究了在不同取代位点共掺入Er ³⁺和Yb ³⁺中的SrTiO ₃多晶体的上转换（UC）发射及其对环境的依赖性。即ABO ₃型钙钛矿中的A位和B位及其对H ₂和O ₂环境退火的响应。在980 nm的近红外激发下，由于Yb ^3+的敏化作用，合成后的样品在Er ³⁺离子的绿色（525和550 nm）和红色（660 nm）区域表现出较强的UC发射特性；A站点掺杂的发射要强于B站点掺杂的发射。有趣的是，在H _2中退火大气中增加氧空位抑制了A部位掺杂样品的光致发光和UC发射，但增强了B部位掺杂样品的发射信号。在随后的O ₂气氛中退火以减少氧空位之后，发射强度显示出返回到刚合成的A位掺杂和B位掺杂样品中的趋势。这些有趣的行为是根据取代位点和电荷补偿之间的关系来解释的。我们进行了与温度相关的UC排放，发现两个绿色排放之间的强度比随温度显着变化。这种强荧光强度比可用于光学测温。