Surface Modification of PEDOT:PSS for Enhanced Performance of Inverted Perovskite Solar Cells

Inverted perovskite solar cells (PSCs) with PEDOT:PSS as hole transporting layers exhibit tremendous prospects for flexible photovoltaic applications owing to their characteristics of low-temperature solution processability and favorable flexibility. Nevertheless, the energy level mismatch of PEDOT:PSS and perovskite layer results in a severe energy deficit. In addition, the acidity of PEDOT:PSS is detrimental to the stability of devices. To address these issues, we employ a glyceryl monostearate (GMS) interlayer to improve the work function and conductivity of PEDOT:PSS. Meanwhile, it can passivate the traps at the interface of PEDOT:PSS/perovskite. As a consequence, the champion power conversion efficiencies of photovoltaic devices based on MAPbI3 films increase from 14.82% to 17.29% due to the surface modification of PEDOT:PSS with GMS, which is mainly ascribed to the enhanced open-circuit voltage and short-circuit current density. Furthermore, the nonencapsulated MAPbI3 perovskite films and devices based on GMS-modified PEDOT:PSS show much better moisture stability and thermal stability than the counterparts without GMS modification.