Potassium Benzoate-Doped PEDOT:PSS for Improving the Open-Circuit Voltage and Power Conversion Efficiency of Inverted Perovskite Solar Cells

Abstract

Inverted perovskite solar cells (IPSCs) have become a research hotspot in the field of photovoltaics due to their excellent photovoltaic performance, minimal hysteresis, and low fabrication costs. Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), as an inexpensive hole transport material, has been widely applied in IPSCs. However, PEDOT:PSS has drawbacks such as energy-level mismatch with perovskite, severe interfacial defects, low hole transport rate, and low conductivity. Therefore, modifying and improving PEDOT:PSS is of practical value. Herein, potassium benzoate is introduced to dope PEDOT:PSS, enhancing its conductivity and accelerating hole transport in the device, making the energy levels between PEDOT:PSS and perovskite more compatible. More importantly, potassium benzoate-doped PEDOT promotes crystal growth, increases the grain size of the perovskite film, and passivates interfacial defects. The open-circuit voltage (V_oc) of the device increases from 1.107 to 1.137 V, and the power conversion efficiency improves from the original 17.24% to 20.15%. This study provides a new approach to develop inverted PSCs.