Enhanced performance and stability of inverted planar perovskite solar cells by incorporating 1,6-diaminohexane dihydrochloride additive

Abstract

Herein, 1,6-Diaminohexane Dihydrochloride (1,6-DD) is introduced into perovskite precursors to fabricate the inverted planar perovskite solar cells. By regulating the concentration of 1,6-DD additive, the average power conversion efficiency (PCE) of perovskite solar cells is enhanced by 20%. The champion device achieves a relatively high PCE of 17% and an excellent fill factor of 80.1%. The PCE of the large-area (1 cm2) device also reaches to 13.68%. After exposure to the air for 16 days, the device with 1,6-DD additive still retains above 90% of the initial efficiency, exhibiting good stability. We demonstrate that a small amount of 1,6-DD affects the crystallization dynamic, yielding ideal perovskite film with enhanced crystallinity and enlarged grain size. The two terminal -NH3+ groups passivates the vacancy defects at the perovskite crystal surface, suppressing charge recombination and facilitating charge transportation effectively. Meanwhile, adjacent crystal surfaces are linked through the hexane alkyl chain of 1,6-DD molecule, which enhances the interaction between perovskite grains and anchors the microstructure of perovskite to some degree. Hydrophobic hexane alkyl chains also increase the moisture resistance of perovskite film. Thus, an easy and effective way is provided for fabricating efficient and stable perovskite solar cells.