High-sensitivity self-powered circularly polarized light detection based on chiral antimony-based halides with strong polarity

Chiral organic-inorganic hybrid halides show significant potential for applications in circularly polarized photodetection, chiral-induced spin selectivity effects (CISS), and nonlinear optics. However, the widespread use of toxic lead element poses environmental concerns, hindering the further applications. Herein, we synthesized a zero-dimensional (0D) lead-free chiral antimony-based halide (R/S-MBA)₄Sb₂Br₁₀ with the coexistence of polarity and crystallographic chirality. The halides exhibit unique magneto-chiroptical effects due to the field-effect-induced fine-tuning of exciton energy, which is the first observation in chiral antimony-based halides. Furthermore, owing to its significant spontaneous polarization (5.0 μC/cm²) and optical chirality (g_CD = 0.0018), (R/S-MBA)₄Sb₂Br₁₀ halide exhibits excellent performance in self-powered circularly polarized photodetection, nonlinear optics, and CISS effects. The self-powered photodetector demonstrates high sensitivity with distinguishable factors (g_res = 0.53/−0.51 @ 0 V) and broad spectral response. The single crystal (R/S-MBA)₄Sb₂Br₁₀ also exhibits a high second-harmonic polarization response asymmetry factor (g_SHG-CD = 0.98/−0.70) and strong second-harmonic generation intensity. These performances are among the best reported for chiral halides. Our research not only sheds new light on the investigation of magneto-chiroptical phenomena, but also marks a significant advancement in realizing high-sensitivity circularly polarized light detection within the realm of lead-free polar materials.