Solution processable self-doped polyaniline as hole transport layer for inverted polymer solar cells

Abstract

Polymer solar cells (PSCs) are a promising alternative for low-cost renewable energy due to their solution-process, flexibility and large-area fabrication. To improve power conversion efficiency (PCE) of PSC, a hole transport layer (HTL) is usually inserted between anode and active layer to enhance hole carrier collection. In this contribution, the utilization of solution processable self-doped sulfonic acid ring-substituted polyaniline (SPAN) thin film as the HTL in inverted PSC (i-PSC) composed of poly(3-hexylthiophene) (P3HT):[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) bulk heterojunction is demonstrated. The i-PSC with SPAN as the HTL exhibits an improvement over that with PEDOT:PSS (from 3.30 ± 0.14% to 3.54 ± 0.11%) due to higher conductivity and better film quality of SPAN relative to poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS), suggesting that SPAN can be a promising alternative to PEDOT:PSS as the effective HTL for i-PSC.