Efficient and stable inverted perovskite solar cells employing self-assembled hole-transporting monolayers with enhanced interface interaction

Molecular tailoring of self-assembled hole-transporting monolayers (SAMs) has been proven as an efficient approach for improving the device performance of inverted perovskite solar cells. Herein, a novel SAM with extended conjugation is designed and synthesized, named NaPh-4PACz. Compared to Ph-4PACz, NaPh-4PACz exhibits a larger adsorption energy with the ITO substrate, enabling the formation of a more uniform and dense film, thereby preventing direct contact between the perovskite and ITO. Additionally, NaPh-4PACz also has a stronger interaction with the perovskite, which can reduce buried interface defects and suppress non-radiative recombination. Consequently, NaPh-4PACz-based devices achieved a power conversion efficiency of 25.48 % due to their interfacial “adhesive” ability. Importantly, the stability of the NaPh-4PACz-based devices was significantly improved.