Hydrazone dye passivator for high-performance and stable perovskite solar cells

There has been rapid development of organic-inorganic perovskite solar cells (PSCs) in recent years, but efficiency and stability challenges remain due to the massive defects in perovskite films. Here, the organic dye Th-azi-Pyr (ethyl 2-(2-(3-methyl-5-oxo-1-phenyl-1,5-dihydro-4H-pyrazol-4-ylidene) hydrazineyl)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylate) with carbonyl, pyrazolone structure, and benzene ring was synthesized and used to prepare high-quality perovskite film as an additive. Th-azi-Pyr formed relatively stable intermediate ligands with uncoordinated Pb and I, slowing the crystal growth and reducing the grain boundary defects of perovskite. In addition, the benzene ring in the dye protected against moisture and increased the stability of the perovskite film. Therefore, the Th-azi-Pyr-modified PSC assembled in an air environment exhibited a promising power conversion efficiency (PCE) of 19.27%, which is superior to the 15.33% of the control PSC. Additionally, 88% of the original performance was maintained after 300 h at 25 ± 5 °C and 50 ± 10% relative humidity, implying that the modified PSCs exhibited greater stability than the untreated PSCs. This work indicates that simple and low-cost organic dyes are excellent defect passivators for high-performance PSCs.