Cs 2 TiI 6 : A potential lead-free all-inorganic perovskite material for ultrahigh-performance photovoltaic cells and alpha-particle detection

The lead contamination and long-term stability are the two important problems limiting the commercialization of organic-inorganic lead halide perovskites. In this study, through an innovative multi-scale simulation strategy based on the first-principle calculations coupling with drift-diffusion model and Monte Carlo method, a new discovery is shed on the vacancy-ordered double perovskite Cs 2 TiI 6 , a potential nontoxic and stable perovskite material for high-performance solar cell and α-particle detection. The excellent photon absorption character and ultrahigh carrier mobility ( μ n = 2.26×10 4 cm 2 /Vs, μ p = 7.38×10 3 cm 2 /Vs) of Cs 2 TiI 6 induce ultrahigh power conversion efficiency (PCE) for both single-junction solar cell (22.70%) and monolithic all-perovskite tandem solar cell (26.87%). Moreover, the outstanding device performance can be remained even in high energy charge particle detection (α-particle) with excellent charge collection efficiency (CCE = 99.2%) and mobility-lifetime product ( μτ h = 1×10 −3 cm 2 /V). Furthermore, to our surprise, the solar cell and α-particle detector based on Cs 2 TiI 6 material are able to withstand ultrahigh fluence proton beam up to 10 13 and 10 15 p/cm 2 respectively, which strongly suggests that semiconductor devices based on Cs 2 TiI 6 material are able to apply in the astrospace. The multi-scale simulation connecting from material to device reveals that Cs 2 TiI 6 perovskite has the great potential for photovoltaic cells, α-particle detection and even their space application.