Study of the effect of DIO additive on charge extraction and recombination in organic–inorganic hybrid MAPbI3−xClx perovskite solar cell

In this article, we fabricated a plane structure perovskite solar cell of ITO/PEDOT:PSS/MAPbI_3−xCl_x/PCBM/Al. With 1% of 1,8-diiodooctane (DIO) additive in the perovskite, the solar cell''s efficiency greatly increased from 10.39% to 13.57%. On the one hand, the DIO additive is advantageous to enhance the thin-film degree of crystallinity, and it can enhance the perovskite thin film''s electrical polarization characteristic, leading to an increase in the built-in electric field, and promote charge extraction and separation and transport processes. On the other hand, the DIO additive can also enhance the charge extraction speed in the perovskite solar cell photoelectric conversion process, and further increase the power conversion efficiency (PCE) of the perovskite solar cell. In addition, in the perovskite solar cell device there occurs the monomolecular recombination effect; the DIO additive introduced into the perovskite can effectively reduce the trap-induced monomolecular recombination effect, and enhance the solar cell''s PCE.

The additive of DIO not only can increase the PCE of perovskite solar cell, but also can decrease the bimolecular recombination.