A Nonionic and Low-Entropic MA(MMA)_nPbI₃-Ink for Fast Crystallization of Perovskite Thin Films

Conventional processing of the halide perovskite usually utilizes ionic precursor solutions containing mobile precursor ions in a high-boiling-point solvent. The assembly of these disordered ions into low-entropic crystals needs to overcome the large thermodynamic energy barrier. Traditional processes rely on high-temperature annealing and complex anti-solvent treatments to overcome this barrier, but they remain highly uncontrollable. Here, we report a novel nonionic and low-entropic MA(MMA)_nPbI₃ ink for fast perovskite crystallization with superior {110} preferred orientation and a high Lotgering factor. And the ink-based films exhibit an extraordinary long carrier diffusion length of 4.6 μm at the single-crystal level. With facial one-step processing, the corresponding photovoltaic cell exhibits a record efficiency of 21.8% based on the MAPbI₃-system. Scaling of active area from 0.096 to 0.5 cm² did not deteriorate the cell performance as the efficiency remained over 21%. These results demonstrate the potential of this nonionic ink for the industrial transition of perovskite photovoltaic technology.