Chiral Doping of Two-Dimensional Molecular Crystals for Circularly Polarized Photodetection

2 Abstract Circularly polarized (CP) photodetection is essential for applications such as quantum communication, biomedical imaging, and secure optical encryption. Direct CP photodetection using chiral organic materials has attracted growing interest owing to their structural tunability and solution processability; however, it requires both strong chiroptical response and efficient charge transport. Two-dimensional molecular crystals (2DMCs) are attractive photoactive systems with ordered molecular packing and favorable charge transport, but lack intrinsic chirality. Here, we develop a chiral doping strategy to introduce chiroptical activity into 2DMCs for efficient CP photodetection. An achiral diphenyl-substituted boron–nitrogen-embedded anthracene derivative bearing hexyl side chains is designed as the host, while chiral molecules with the same conjugated backbone and chiral side chains serve as dopants. The resulting doped films combine chiroptical response with ordered molecular packing. The corresponding phototransistor devices exhibit favorable charge transport and ultraviolet CP photodetection performance, with a maximum mobility of 0.45 cm 2 V −1 s −1 , a maximum responsivity of 8.2×10 2 A W −1 , and an average photocurrent dissymmetry factor of 0.17, representing competitive performance among reported direct organic CP phototransistors. Furthermore, CPlight-based information encoding and decoding are demonstrated. This strategy endows 2DMCs with chiroptical activity, providing a platform for CP photodetection and chiral optoelectronic applications.