Lanthanide ion doping enabling highly sensitive and stable all-inorganic CsPbI2Br perovskite photodetectors

Abstract

All-inorganic perovskites have been widely explored for high-performance photodetectors (PDs), owing to their high carrier mobility, long carrier diffusion length, and excellent visible light absorption, etc. However, the poor film quality of solution-prepared all-inorganic perovskites inevitably limits the development of PDs. Here, we present the successful incorporation of lanthanide ions (Ln³⁺ = Pr³⁺, Gd³⁺, Nd³⁺, Eu³⁺, Tm³⁺, Ho³⁺, and Yb³⁺) into all-inorganic CsPbI₂Br films to significantly improve the film quality and largely enhance the performance of PDs. Arising from the enlarged grain size and enhanced crystallinity of perovskite films upon Ln³⁺ doping, the detectivity (D*) and stability of PDs are significantly improved. In particular, PDs with Yb³⁺ doping achieve the best performance, and display an effective response range of 300–700 nm and quick response time (640 ns) with a D* of 4.6 × 10¹² Jones in contrast to 3.7 × 10⁹ Jones for pristine PDs. These findings offer new insights into the development of high quality perovskite films and highly sensitive and stable PDs.