Enhanced performance and stability of quasi two-dimensional perovskite solar cells by conductive phosphine oxide

Abstract

Recently, quasi two-dimensional (quasi-2D) perovskite solar cells (PSCs) have been paid more attentions due to their good stability. While the efficiency of 2D PSCs is lower than that of 3D ones due to their poor charge transport property. Here we introduced a conductive material of 2,7-bis(diphenylphosphoryl)-9,9′-spirobifluorene (SPPO13) into the precursor solution of quasi-2D perovskite GAMA5Pb5I16 (GA = guanidinium, MA = methylammonium) to improve the charge transfer property. The efficiency of the PSCs with SPPO13 is increased to 18.58 % from 16.97 % for the control, which is resulting from the enlarged grain size, increased electrical conductivity, and reduced trap state density induced by the addition of SPPO13. Moreover, the additon of SPPO13 improves the stability of the devices. The normalized PCE of the devices with SPPO13 keeps 90 % of the original value after aging for 30 days in atmosphere. This study provides a novel way to enhance the charge transfer property of 2D perovskite by conductive material for enhanced efficiency and stability of quasi-2D PSCs.