All-inorganic micrometric CsPbBr3:Yb3+ powder as a multifunctional material for photovoltaics and optical thermometry: structural and optical characterization

Halide perovskites have been studied very intensively by researchers during the last decade. Development of these materials has improved their unique optoelectrical properties reaching even higher standards making them promising candidates for photovoltaic applications. It should be noted that most inorganic halide perovskites obtained to date are synthesized using organic solvents in the form of nanosized colloids. Here, a low-temperature synthesis protocol for the preparation of microcrystalline CsPbBr3 perovskite powder doped with Yb3+ ions is proposed. The structural and photoluminescence features of the studied material have been thoroughly investigated and described. It turned out that the excitation of the CsPbBr3:Yb3+ perovskite with a 375 nm wavelength leads to spontaneous luminescence of excitons and Yb3+ ions. Hence, the use of CsPbBr3:Yb3+ as a luminescent thermometer or an additional absorbing layer on a solar cell surface is possible. The latter application may result in an increase in the conversion efficiency of the cell. In order to verify this, such a layer was prepared and installed on a commercial silicon solar cell. Its photovoltaic properties have been investigated by the measurements of current-voltage characteristics with 1-sun illumination and spectral characteristics of external quantum efficiency.

近十年来，研究人员对卤化物钙钛矿（Halide perovskites）开展了极为深入的研究。这类材料的发展使其独特的光电性能持续优化，性能标准进一步提升，成为光伏应用领域极具潜力的候选材料。需要说明的是，迄今制备的大多数无机卤化物钙钛矿均以有机溶剂为介质，合成为纳米胶体形态。本研究提出了一种低温合成工艺，用于制备掺杂Yb³+离子的微晶态CsPbBr₃钙钛矿粉末。研究人员对该材料的结构与光致发光（photoluminescence）特性进行了全面的表征与分析。结果表明，采用375 nm波长激发CsPbBr₃:Yb³+钙钛矿时，会触发激子与Yb³+离子的自发发光。因此，CsPbBr₃:Yb³+可作为发光温度计，或应用于太阳能电池表面的附加吸光层。后一种应用有望提升太阳能电池的光电转换效率。为验证这一设想，研究人员制备了此类附加吸光层并将其搭载于商用硅基太阳能电池上。通过1太阳光照（1-sun illumination）下的电流-电压特性（current-voltage characteristics）测试以及外量子效率（external quantum efficiency）光谱特性测量，对该电池的光伏性能进行了系统表征。