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, NO 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 cmx5 cm device reaches up to 11.2%, which can be applicable to the preparation of large-area perovskite solar cells.