Helical donor-acceptor bulk heterojunctions for dissymmetric circularly polarized light detection

초록

Direct detection of circularly polarized light using chiral organic semiconductors significantly advances the development of next-generation photonic technologies. However, fabrication of a bulk heterojunction (BHJ) in a chiroptical active layer, which is expected to enhance spin-selective photocurrent, remains challenging due to disruptions caused by achiral counterparts. Here, we present a novel chiral donor-chiral acceptor-based BHJ layer for high-performance circular polarization (CP) photodetectors. Simultaneous helical rearrangements of both donor and acceptor polymers, with overlapping chiroptical spectra, yield a highly dissymmetric BHJ layer. The CP photodetectors exhibit a high photocurrent dissymmetry factor of 0.53 and superior photodetection characteristics due to effective exciton separation. We investigate chiroptical photodynamics of a CP beam interacting with chiral BHJ films and fabricate a prototype, real-time, large-area CP photodetector array. This work represents a significant step toward high-performance, miniaturized, and integrated CP photodetectors, with applications in quantum computation, spin-encoded optical communication, high-resolution polarization imaging, and ellipsometric tomography.

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