Efficient Optical Orientation and Slow Spin Relaxation in Lead-Free CsSnBr3 Perovskite Nanocrystals

Spin properties of lead halide perovskites have recently received considerable research attention, because the strong spin-orbit coupling (SOC) enables facile optical orientation of spin-polarized states, a property particularly useful for information science and spintronics. The strong SOC, however, also limits the spin relaxation lifetime. Herein, we study optical orientation and spin relaxation in lead-free CsSnBr3 perovskite nanocrystals. The SOC of CsSnBr3 (similar to 0.43 eV) is 3.5-fold weaker than that of lead halide perovskites but is still strong enough to ensure efficient optical orientation. Meanwhile, the room-temperature spin lifetime is prolonged to 18 +/- 2 ps, longer than the reported lifetimes of various lead halide perovskites, and it is likely limited by electron-hole exchange rather than SOC. These results demonstrate the strong potential of nontoxic tin halide perovskites for spin-related applications.

Automated summary

The spin properties of lead-free CsSnBr3 perovskite nanocrystals were studied, revealing that despite weaker spin-orbit coupling compared to lead halide perovskites, efficient optical orientation is still possible and a longer spin lifetime was observed. These findings demonstrate the strong potential of non-toxic tin halide perovskites for spin-related applications.