Efficiency enhancement in planar CH3NH3PbI3−xClx perovskite solar cells by processing with bidentate halogenated additives

•Bidentate halogenated additives were added into the precursor solution of perovskite.•The optimized additive of DIO could improve perovskite film quality.•We analyzed the mechanism of the chelation between DIO and Pb2+.•The PSC device incorporating the 2 wt%DIO achieved a maximum PCE of 19.1%.

A simple but effective method for improving the perovskite film quality by adding bidentate halogenated additives into the precursor solution of perovskite was proposed. By comparing and analyzing the effects of the use of different additives on the film-forming performances, DIO was selected as the optimal additive. The optimal additive amount of DIO could contribute to a more uniform and non-defective growth of perovskite crystal nucleation, enabling preparation of the smooth and compact film with large grain size. The effect mechanism of the chelation between DIO and Pb2+ on the film-forming process of perovskite crystal was also analyzed. The PCE of the PSC device incorporating the DIO is runned up to 19.1%, accounting for a 73.6% enhancement as compared to pre-optimized control PSCs. Conclusively, using the proposed technology, the conversion efficiency of the prepared 5 cm×5 cm device reaches up to 11.2%, which can be applicable to the preparation of large-area perovskite solar cells.

Graphical abstractA simple but effective method for improving the perovskite film quality by adding bidentate halogenated additives into the precursor solution of perovskite was proposed. The optimized additive of DIO could contribute to a more uniform and non-defective growth of perovskite crystal nucleation, leading to prepare the smooth and compact film with large grain size. The PCE of the PSC device incorporating the DIO is runned up to 19.1%, accounting for a 73.6% enhancement as compared to pre-optimized control PSCs.Download high-res image (276KB)Download full-size image