Effect of Zinc‐Doping on the Reduction of the Hot‐Carrier Cooling Rate in Halide Perovskites
Qi Wei, Jun Yin, Osman M. Bakr, Ze Wang, Chen‐Hao Wang, Omar F. Mohammed, Mingjie Li, Guichuan Xing
Abstract
Abstract The fast hot‐carrier cooling process in the solar‐absorbers fundamentally limits their photon‐conversion efficiencies. It is highly desirable to develop a solar absorber with long‐lived hot‐carriers at sun‐illumination intensity, which can be used to develop the hot‐carrier solar cells with enhanced efficiency. Herein, we reveal that zinc‐doped (0.34 %) halide perovskites have the slower hot‐carrier cooling compared with the pristine sample through the transient absorption spectroscopy measurements and theoretical calculations. The hot‐carrier energy loss rate at the low photoexcitation level of 10 17 cm −3 is found to be ≈3 times smaller than that of un‐doped perovskites for T=500 K hot carriers, and up to ten times when the hot‐carrier temperature approaches the lattice temperature. The incorporation of zinc‐dopant into perovskites can reduce the nonadiabatic couplings between conduction bands, which retards the photogenerated hot‐carriers relaxation processes. Our findings present a practical strategy to slow down the hot‐carrier cooling in perovskites at low carrier densities, which would be invaluable for the further development of practical hot‐carrier photovoltaics based on perovskites.