Exposed the mechanism of lead chloride dopant for high efficiency planar-structure perovskite solar cells

Abstract Although the PbCl 2 has been exploited to improve the performance of perovskite solar cells, the mechanism of enhancement by the introducing PbCl 2 is not fully understudied. In present work, we used the PbCl 2 as a dopant to improve the perovskite film quality, we found the crystalline and grain size of perovskite film both increased with 10% molar ratio of PbCl 2 . The in situ time-resolved grazing incidence wide-angle X-ray scattering measurements revealed that more pre-nucleated suspended in the solution when employed the PbCl 2 dopant, leading to high crystalline for perovskite film. An incorporation of the space charge limit current, photoluminescence, time-resolved photoluminescence measurements, we uncover the function of PbCl 2 in reduced trap density, decreased charge recombination and enhanced carrier lifetime. As a result, the efficiency of planar-structure perovskite solar cells based on PbCl 2 enhanced to as high as 19.79% with reduced hysteresis, increased by ∼23% compared to the device without PbCl 2 (16.05%). We believe that this work would provide a fundamental prospective for mixed perovskite and promote its application in perovskite photovoltaics.