Electron Acceptors Based on Resonant N─B←N Unit with Improved Exciton Dissociation for High‐Performance Short‐Wavelength Infrared Organic Photodetectors

Abstract

AbstractDevice performance of photodiode‐type short‐wavelength infrared (SWIR) organic photodetectors (OPDs) is largely limited by poor exciton dissociation. In this work, we reported that downshifted highest occupied molecular orbital energy level (EHOMO) and increased electrostatic potential (ESP) of electron acceptor lead to improved exciton dissociation and consequently enhanced SWIR OPD device performance. Tetramers of thiophene‐fused 4,4‐difluoro‐4‐bora‐3a,4a‐diaza‐s‐indacene (TF‐BODIPY) unit represent a new kind of electron acceptors with SWIR photoresponse. By endcapping the TF‐BODIPY tetramer with electron‐deficient pentafluorophenyl groups, we downshift the EHOMO of the electron acceptor by 0.06 eV and increase the ESP of the electron acceptor by 89 meV. As a result, the OPD devices of the electron acceptor exhibit SWIR photoresponse in the wavelength range of 0.3–1.3 µm with a maximum specific detectivity (D*) of 1.04 × 1012 Jones and a responsivity (R) of 0.16 A W−1 at 1.12 µm. This performance is among the highest reported for SWIR OPDs.