Chiral Nanographene Imides: Balancing the Dissymmetry Factor-Mobility Trade-Off Towards Circularly Polarization-Sensitive Photodetection.

Chiral small-molecule organic semiconductors are attractive for circularly polarized light (CPL) detection owing to their tunable functionality and versatile processability. However, their intrinsic trade-off between large dissymmetry factor and high carrier mobility (μ) hinders the application for high-performance CPL detection. To overcome this issue, the chiral induction combined with the ring-fusion strategy is employed to rationally construct a new n-type chiral nanographene imide (S)-Cy-FT-FPDI. In the monomeric state, (S)-Cy-FT-FPDI exhibited distinct circular dichroism (CD) signals, with the maximum absorption dissymmetry factor (gabs) reaching -2.16 × 10-3. The (S)-Cy-FT-FPDI annealed thin films presented dual-wavelength CPL responses at 455 and 595 nm, with photocurrent dissymmetry factors (gph) of 0.22 and 0.53, respectively, while delivering high μ of 0.57 cm2 V-1 s-1, successfully balancing the favorable electrical performance and excellent chiroptical property. Remarkably, the achieved μ and gph outperform most of the previously reported chiral organic small-molecule counterparts. Then, we have successfully demonstrated the high-fidelity encoding and encryption based on (S)-Cy-FT-FPDI annealed thin films. Our work provides a feasible molecular design strategy for chiral organic small molecules with concurrent high gph and μ, balancing the dissymmetry factor-mobility trade-off towards high-performance CPL detection.