Emission Mechanism of Self-Trapped Excitons in Sb3+-Doped All- Inorganic Metal-Halide Perovskites

Sb3+ doping confers highly efficient and color-diverse broadband light emission to all-inorganic metal-halide perovskites. However, the emission mechanism is still under debate. Herein, a trace amount of Sb3+ ions (<0.1% atomic percentage) doping in the typical all-inorganic perovskites Cs2NaInCl6, Rb3InCl6, and Cs2InCl5 center dot H2O allows universal observation of the fine structure in the photoluminescence excitation spectrum of the ns2 electron. A lifetime mapping method was utilized to reveal the origin of broadband emission triggered by Sb3+ doping, by which various fluorescence components can be differentiated. In particular, free-exciton emission was identified at the high-energy end of the broadband emission for all three doped systems. The excitation -energy-and temperature-dependent fluorescence decay further indicates the existence and origin of self-trapped states. The observed structural and vibrational symmetry-dependent emission behaviors suggest dipole interactions can dramatically alter Stokes-shift energy and modulate the light-emitting wavelength.

Automated summary

Sb3+ doping in all-inorganic metal-halide perovskites enables highly efficient and color-diverse broadband light emission. The study reveals the origin of this emission and distinguishes various fluorescence components using a lifetime mapping method. The presence of free-exciton emission and self-trapped states is also identified.