Abstract: Perovskite films prepared by CH3NH2 molecules at ambient conditions have led to rapid fabrication of perovskite solar cells (PSCs), but lack of mechanistic studies and inconsistencies with operability in their production. Here, the structure of CH3NH2-CH3NH3PbI3 crystals was analyzed to be involved with hydrogen bonds (CH3NH2CH3NH3+) and guide the facile, reproducible preparation of high-quality perovskite films at ambient conditions. Hydrogen bonds within CH3NH2CH3NH3+ dimers were found in the CH3NH2-CH3NH3PbI3 intermediates, accompanied by 1D-PbI3- chains (δ-phase). The weakly hydrogen-bonded CH3NH2 molecules were easily released from the CH3NH2-CH3NH3PbI3 intermediates, contributing to rapid, spontaneous phase transition from 1D-PbI3- (δ-phase) to 3D-PbI3- (α-phase). Further introducing CH3NH3Cl into the CH3NH2-CH3NH3PbI3 intermediates led to interruption of 1D-PbI3- into 0D-Pb2I9-xClx5- (0˂x˂6), adjusting the phase transition route towards 3D-PbI3-. Based on above understanding, CH3NH2 solution in ethanol and CH3NH3Cl were used for precursors and a champion efficiency of 20.3% in PSCs was achieved. Large-scale modules (12-cm2 aperture area) fabricated by a dip-coating technology exhibited an efficiency up to 16.0% and outstanding stability over 10,000 s under continu-ous output. The developed preparation method of perovskite precursors and insightful research of methylamine-dimer-induced phase transition mechanism are ready for the high-quality perovskite films with robust operability, showing great potential for large-scale com-mercialization.

Source:https://pcss.xmu.edu.cn/en/info/1095/1869.htm

Full-Link:https://pubs.acs.org/doi/10.1021/jacs.9b13443