Mitigating voltage losses and strain in perovskite solar cells through precise microscopic arrangement of chemical monomers

Abstract Organic–inorganic halide perovskite solar cells (PSCs) have attracted substantial attention as their superior photovoltaic performance. Nevertheless, due to the solution fabrication process, the distribution of the chemical monomer in the precursor is difficult to orderly control, culminating in the generation of stress and non‐radiative recombination in the annealed films. This results in the degradation of open‐circuit voltage ( V oc ) and power conversion efficiency (PCE) of the cells, deteriorating the stability of the PSCs. To address these challenges, we precisely control the microscopic arrangement of chemical monomers in the precursor and the crystallization kinetics of the films by introducing the 1,4‐benzenedicarboximidamide dihydrochloride (TAD) molecule. The –C=N functional groups in the TAD can anchor on the [PbI 6 ] 4− monomers, and the distance between the two –C=N functional groups is slightly smaller than the Pb–Pb space of the [PbI 6 ] 4− monomers, promoting the dominance growth of the (001) plane. The approach effectively minimizes recombination loss from stress‐induced defects, yielding a remarkably low voltage loss ( V loss ) of 0.32 V and offering a reliable method to overcome the detrimental strains in PSCs.