Solvents donor number modulation induced energy level alignment enables high-performance perovskite solar cells for long-endurance drones

Antisolvents play a vital role in the one-step solution deposition method for fabricating efficient perovskite solar cells (PSCs). However, the widely used chlorobenzene (CB) antisolvent does not expel the residual host solvent dimethyl sulfoxide (DMSO) due to their weak interaction, leading to defects and voids in the perovskite films. Herein, ethyl acetate was strategically introduced into CB to modulate the donor number and coordination capacity of the antisolvent, enabling efficient extraction of residual DMSO and considerably reducing defects and voids in the films. Importantly, the optimized antisolvent adjusted the energy level of the perovskite films, thus reducing the energy barrier between the electron transport layer and the perovskite films. This energy-level alignment enhanced the electron extraction and suppressed nonradiative recombination. Consequently, an outstanding open-circuit voltage of 1.254 V was achieved, representing the highest reported value among the highly efficient PSCs (Efficiency > 23 %). The devices delivered efficiencies of 24.71 % and 20.05 % for the small-area device and module, respectively. A solar hybrid energy supply system comprising 16 interconnected modules was then successfully assembled and used to power a tilt-rotor drone, achieving a 10.45 % extension in flight time compared to the battery-only system.