Rapid Surface Reconstruction in Air‐Processed Perovskite Solar Cells by Blade Coating

Abstract

Blade coating has been developed to be an essential technique for large‐area fabrication of perovskite solar cells (PSCs). However, effective surface treatment of the perovskite layer, which is a critical step for improving PSC performance, remains challenges during blade coating due to the short interaction time between the modification solution and the perovskite layer, as well as the limited selection of available organic solvents. In this study, a novel modifier N,N‐diphenylguanidine monohydrobromide (DPGABr) dissolved in acetonitrile (ACN) is blade coated on the MA0.7FA0.3PbI3 surface in air to reconstruct the perovskite surface in hundreds of milliseconds. This work finds that the solvent ACN rapidly dissolves organic iodide of the perovskite layer and leads to a PbI2‐rich surface, providing reactive sites for DPGABr to form a thin DPGABr/PbI2 complex layer. This surface reconstruction can effectively passivate defects and induce n‐type doping on the perovskite surface to facilitate electron transfer. The resultant devices show a 15% improvement in average power conversion efficiency. More importantly, the devices with the surface reconstruction show outstanding long‐term stability, with negligible performance degradation even after 1‐year storage in air. This study presents a convenient and effective approach for improving the performance of blade‐coated PSCs prepared in air.

Synergistic Effect of Alkylammonium Chlorides to Trigger an Ultrafast Nucleation for Antisolvent‐Free Perovskite Solar Cells Processed from 2‐Methoxyethanol

“…are incorporated to 2ME solvent system. As listed in Table S1 (Supporting Information), [19][20][21][22][23][24][25][26][27][28] the previous studies were incorporating the strongly coordinating solvents in 2ME system to form intermediate phase for balance nucleation and crystal growth, and to obtain high quality perovskite films. However, Huang's group has revealed that non-volatile solvent additives, such as DMSO inevitably leave voids in the perovskite films near the perovskite-substrate interfaces because of the delay in the non-volatile solvents escaping from the bottom.…”

A Double Compatibilization Strategy To Boost the Performance of p–i–n Solar Cells Based on Perovskite Deposited in Humid Ambient Air

“…Moreover, although this architecture is preferred for the ease of scalability due to its fabrication at mild temperatures and cost-efficiency, there are still only a limited number of reported examples, particularly of perovskite deposition in ambient air . Indeed, the poor wettability of the hydrophobic hole transporting layer (HTL) by the perovskite inks, which prevents the full coverage of the film and thus degrades the device performance, has hampered the demonstration of high-efficiency p – i – n FAPI. − In general, the wettability issue has been partially mitigated for different perovskites deposited in a controlled inert environment by different approaches, including the use of interfacial modifications for example with large organic cations such as 4-fluoro-phenylethylammonium iodide (F-PEAI) and the use of additives in the perovskite’s solution like polymers such as poly(vinylpyrrolidone) (PVP) and polymeric starch . The use of surfactants as additives has been explored in the literature, although not for FAPI perovskite.…”