The Polymer Society of Korea

Abstract

Conventional OPD research has relied on thick active layers (200–300 nm) or charge-blocking interlayers to suppress dark current, but these approaches cause photocurrent loss and complexity. This study introduces a PM6 polymer donor overlayer onto a high-acceptor-content (90% IT4F) bulk heterojunction via low-temperature solution coating, achieving low dark current and high detectivity with a thin ~130 nm active layer. High-acceptor layers enable efficient electron transport but also increase dark current through electron injection pathways. The PM6 overlayer blocks electron injection while assisting hole collection, effectively suppressing dark current without sacrificing charge extraction.