Organic Planar Heterojunction Solar Cells and Photodetectors Tailored to the Exciton Diffusion Length Scale of a Non‐Fullerene Acceptor

• DOI: 10.1002/adfm.202208001
• Publication Date: 2022-10-19T01:55:34Z
• Authors: Tack Ho Lee; Yifan Dong; Richard A. Pacalaj; Song Yi Park; Weidong Xu; Ji‐Seon Kim; James R. Durrant
• Keywords: Acceptor; Active layer

Abstract While non‐fullerene acceptors (NFAs) have recently been demonstrated to exhibit long‐range exciton diffusion, most organic photovoltaic and photodetector studies still focus on blended polymer: NFA systems. Herein, a 40 nm diffusion length for IT4F excitons is determined, it that sharp interface, planar heterojunction (PHJ) IT4F/PM6 devices with the layer thickness matched this yield optimized performance. The PHJ an enhanced device open‐circuit voltage relative bulk (BHJ) devices, associated suppressed bimolecular recombination losses. architecture also results in ≈100‐fold increase electroluminescence (EL) quantum efficiency BHJ device, correlated shift from charge transfer state EL dominated PHJ, attributed significant hole injection PM6 into IT4F. Of particular note, shown suppress dark leakage current, resulting 83 times higher detectivity at −2 V bias than equivalent device.