The Polymer Society of Korea

Abstract

Organic solar cells (OSCs) have shown significant progress in recent decades, accompanied by improvements in electron transporting layers (ETLs). Among various ETL materials, PDINN demonstrates excellent electron transport in devices by controlling the work function of the electrodes due to its self-doping ability. However, the low glass transition temperature of PDINN causes inferior thermal stability in OSCs, despite achieving a high power conversion efficiency (PCE). Herein, we designed a series of perylene diimide-based polymers to suppress the thermal movement of the ETL molecules. The molecular weight was controlled in the medium (M) and high (H) batches to manipulate solubility. PPV-M, the ETL polymer which contains a vinyl linker group with a moderate molecular weight, demonstrated the highest PCE of 18.45% in OSC device applications, with enhanced thermal stability among the ETLs. In contrast, PDINN-based OSCs achieved a PCE of 17.79% and showed the lowest thermal stability.