Slowing the hot‐carrier cooling by an organic small molecule in perovskite solar cells

Abstract Harvesting hot carriers (HCs) before thermalizing to the perovskite crystal lattice is very promising for advancing the efficiency of perovskite solar cells (PSCs) towards the Shockley–Queisser limit. Thus, it is very crucial to slow down the HCs cooling process in lead halide perovskites. Herein, we investigated the HCs cooling dynamics of perovskite films in the presence of an organic small molecule, 2,5‐thiophenedicarboxylic acid (TDCA). We found that adding TDCA into perovskite films can efficiently retard HCs cooling process, which favors extracting the excess energies of HCs through carrier transport layers and reducing electron–hole recombination, resulting in enhanced performance in TDCA modified device. Moreover, TDCA can effectively passivate unsaturated Pb²⁺ defects of perovskite films while promoting a preferential crystal orientation. Consequently, the PSCs efficiency is enhanced to 22.85% (TDCA) from 19.96% (control). These findings provide important insight for understanding HCs transfer dynamics and developing next‐generation perovskite‐based HCs optoelectronic devices. image