Chiral Organo-Soluble Carbon Nanocolloids with Dual-Mode Optical Responsiveness: From Nonpolar Enantioselective Sensing to Lead−Halide Perovskite Passivation

A major challenge in chiral carbon nanoparticles is to create materials whose chirality persists outside aqueous environments and remains functional under organic synthesis, interfacial engineering, and device fabrication conditions. We overcome this barrier by developing intrinsically chiral, organo-soluble carbon nanocolloids (CNCs) through solvent-free thermal condensation of enantiopure α-methylbenzylamine with formamidinium salts at 180 °C. Unlike conventional surface-functionalized chiral carbon dots, these CNCs form amorphous carbon-nitrogen-oxygen networks with covalently embedded chiral amidinium chromophores, as confirmed by experimental studies and molecular dynamics simulations. The resulting nanoparticles (5-10 nm in size) are easily dispersible in both polar and nonpolar solvents while maintaining their structural integrity, which is demonstrated by retention of nonvibrational photoluminescence bands in Cl-containing solvents. Chiral CNCs display both bright blue emission (quantum yield up to 40%) and distinct circular dichroism signals (|g| = 3.1-3.7 × 10-4) spanning 250-450 nm in spectral range. Using these CNCs, we demonstrate enantioselective sensing of chiral amines in toluene via dual modulation of photoluminescence and circular dichroism, and passivation of CsPbBr3 perovskite films, which simultaneously enhances their emission intensity and ambient stability. This study introduces a novel class of intrinsically chiral CNCs bridging molecular stereochemical precision with nanoscale colloidal stability for advanced chiral optoelectronics and sensing in organic media.