Universal Ion Migration Suppression Strategy Based on Supramolecular Host-Guest Interaction for High-Performance Perovskite Solar Cells.

The migration of multiple chemical species is are main factor leading to the intrinsic instability of perovskite solar cells (PSCs). Herein, a universal ion migration suppression strategy is innovatively reported to stabilize multiple functional layers by simultaneously suppressing the migration of multiple mobile chemical species based on host-guest interaction via calixarene supramolecules. After incorporating 4-tert-butylcalix[8]arene (C8A), the interfacial defects are passivated, suppressing trap-assisted nonradiative recombination. Moreover, the p-doping of Spiro-OMeTAD is facilitated, and the extraction and transport of holes are promoted for n-i-p regular PSCs. The C8A doped regular devices based on the two-step perovskite deposition method achieve a power conversion efficiency (PCE) of 26.01% (certified 25.68%), which is the record PCE ever reported for the TiO₂-based planar PSCs. The C8A passivated p-i-n inverted PSCs obtain a champion PCE of 27.18% (certified 26.79%), which is the highest PCE for the PSCs using the vacuum flash evaporation method. The resulting unsealed inverted device retains 95% of its initial PCE after 1015 h of continuous operation at maximum power point. This work provides a feasible and effective avenue to address the intrinsic instability of perovskite-based photovoltaics and other optoelectronic devices.