Defect structure in quantum-cutting Yb3+ -doped CsPbCl3 perovskites probed by x-ray absorption and atomic pair distribution function analysis

Lead halide perovskite materials doped with lanthanides can exhibit over 100% luminescence quantum yield due to quantum cutting. Defect states related to these dopants are known to play a role in the quantum cutting mechanism, but the structural changes and charge compensation mechanisms induced by these dopants have not been fully explored. Here, the authors use a combination of advanced x-ray techniques and computational modeling to elucidate the structural impact of ytterbium doping in CsPbCl${}_{3}$. The authors find that Yb${}^{3+}$, exclusively in the +3 oxidation state, replaces Pb${}^{2+}$ in the octahedral site with charge compensated by Pb${}^{2+}$ vacancies, providing clear experimental verification of a hypothesized structure.