Realization of High-Efficiency Inverted Planar Perovskite Solar Cells Based on PEDOT: PSS Doped with Lithium Fluoride

Abstract

The photovoltaic performance of perovskite solar cells with inverted structure depends on the conductivity of the hole transport layer and the charge transport rate to some extent. To further enhance the effect of the hole transport layer, lithium fluoride (LiF) was doped into poly (3,4-ethylene dioxythiophene)-polystyrene sulfonic acid (PEDOT: PSS) to improve its rate of conductivity and interfacial charge transport. The optimal photoelectric conversion efficiency of LiF-based perovskite solar cells that dope hole transport layer is 20.32% with negligible hysteresis, which is much higher than that of the control group (16.70%). Among all photovoltaic parameters, the improvement of open circuit voltage and fill factor is significant. LiF can not only promote the electrical characteristics of PEDOT: PSS and its hole mobility, but also optimize the quality of the upper perovskite film. Perovskite film shows a crystal orientation more conducive to hole transport on the modified hole transport layer, which obtains a dense and smooth absorption layer film. In this study, PEDOT: PSS-based perovskite solar cells with inverted structure doped with LiF are prepared, which provides a simple and effective method to commercialize perovskite solar cells.