Charge-Carrier Dynamics of Lead-Free Halide Perovskite Nanocrystals

≤ 1) NCs, which exhibited a similar 3D cubic perovskite structure to that of the lead-perovskite NCs. The charge-carrier dynamics indicated that the sub-band-gap exciton trapping processes were dominated by ultrafast (∼1-2 ps) intrinsic self-trapping and trapping at surface defects (∼50-100 ps). While trapping at surface defects can be passivated using surfactants, the self-trapping processes is due to the giant carrier-phonon coupling effect. By designing direct band gap double perovskite NCs to tune the sub-band-gap trapping processes, bright dual-color emission was achieved. Furthermore, the violet PLQE could be improved to 36.6%, which is comparable to that in lead halide perovskite NCs. We hope this Account will deepen the understanding of the charge-carrier dynamics in lead-free perovskite NCs and guide the design of high-performance lead-free perovskites.