All‐Inorganic Micrometric CsPbBr₃:Yb³⁺ Powder as a Multifunctional Material for Photovoltaics and Optical Thermometry: Structural and Optical Characterization

Abstract 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 have been 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 are thoroughly investigated and described. It turns 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 is prepared and installed on a commercial silicon solar cell. Its photovoltaic properties are investigated by measurements of the current–voltage characteristics with 1‐sun illumination and the spectral characteristics of the external quantum efficiency.