Trap-assisted circularly polarized organic photodetector

Abstract

Abstract The innovative design of π-conjugated molecules enables the creation of chiral π-systems that selectively interact with circularly polarized light. In circularly polarized organic photodetectors, the use of π-conjugated molecules with highly dissymmetric circularly polarized absorption has been a key strategy for achieving strong differential electrical signals with circularly polarized light. However, factors beyond absorption that influence asymmetric device behavior remain insufficiently explored. In this work, we demonstrate trap-assisted circularly polarized organic photodetectors based on blend systems containing small amounts of achiral acceptors, enabling asymmetric trap filling depending on the handedness of circularly polarized light. Modulated trap dynamics play a crucial role in asymmetric charge extraction, significantly enhancing circularly polarized selectivity. We realize a large-area organic circularly polarized imaging system (4096 pixels) and showcase its potential for real-time visual encryption. This study presents a design strategy for efficient circularly polarized photodetectors with tailored carrier dynamics.