Strengthened Charge-Selective Perovskite/SAM Heterocontact for Efficient and Durable Perovskite Solar Cells via...

Hole-selective self-assembled molecular (SAM) layer plays a critical role in driving the optoelectronic performance of inverted perovskite solar cells (PSCs). Nevertheless, the inherent aggregation of SAMs at the buried heterocontact that causes large energy loss and severe instability, strongly hinders PSCs' practical deployment. Herein, we propose an effective in situ strategy of reconfiguring a robust buried hole-selective heterocontact between SAM and perovskite to promote charge extraction with improved energetics, while suppressing the formation of interfacial voids and defects. We also demonstrate that thermally activated polymerization network densely covers the SAM at the heterocontact, minimizing underlying electrode exposure and preventing upper perovskite decomposition. Simultaneously, perovskite film directly grown on network exhibits a higher crystallinity, along with releasing the residual stress. Consequently, the PSC achieves an impressive efficiency of 26.87% for 1.57 eV bandgap cells and one of the highest fill factors of 87.04% reported so far. Encouragingly, the modified device features an excellent thermal and operational stability, significantly advancing the progress of PSCs toward industrialization.