Improving the Performance of Organic Perovskite Solar Cells by Additive Engineering with 6-Aminonicotinic Acid

The disordered distribution of defects in perovskite structures seriously disrupts the carrier transmission rates and limits the power conversion efficiency (PCE) in perovskite-based solar cells. Defect passivation is an effective strategy to eliminate defects in perovskites and suppress the process of nonradiative recombination. Herein, 6-aminonicotinic acid (6-ANA, C6H6N2O2), which contains both amino and carboxyl groups, has been used, as a crosslinking agent, between perovskite grain boundaries, which allows for the development of efficient and stable perovskite solar cells (PSCs). The passivation mechanism of 6-ANA that enables the fabrication of highly efficient and stable PSCs has systematically been investigated in this study. The results show that the crystallinity of the perovskite film improves with the addition of 6-ANA in the perovskite films and the trap density is suppressed. The optimized efficiency achieved for the PSC device is as high as 19.71% while maintaining an initial efficiency of 75% after 500 h of shelf storage. This work provides a simple and effective strategy to reduce electronic defects, present in perovskite films, as well as at the interface between the perovskite films and the hole transport layers.