Polystyrene‐sulfonate‐doped polypyrrole: Low‐cost hole transport material for developing highly efficient organic solar cells
Swarup Biswas, Yongju Lee, Young‐Jun You, Jae Jin Chung, Jae Won Shim, Hyeok Kim
Abstract
The hole transport layer (HTL) is a vital part in an organic photovoltaic (OPV) device for improving hole extraction ability. The HTL of OPV devices is typically prepared using poly (3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS). However, it presents several disadvantages, including causing deterioration of the active layers, exhibiting sensitivity to ultraviolet radiation, and possessing a short lifespan. Hence, focus has increased on alternative p-type semiconductors with improved environmental stability, easier processing, and higher conductivity. In this study, we prepare water-stable, low-cost, and low-acidity PSS-doped polypyrrole (PPY) with varying PSS concentrations for use as the HTL in OPV devices. The films formed using PPY:PSS exhibit an extremely high transmittance within the visible range. The PPY:PSS HTL-based OPV may reach to highest power conversion efficiency of 5.0% (ie, 11% higher than a PEDOT:PSS-based one) when using an optimal PSS concentration in PPY.