Substituent Modulation in Chiral Triarylboranes: Aggregation-Enhanced Chirality, Photoinduced Crystallization, and Cascaded Afterglow

Chiral luminescent materials integrating multiple photofunctions are highly desirable yet challenging to construct. Herein, we demonstrate that modulating the number of chiral alkoxy groups in triarylboranes effectively controls aggregation behavior, photophysical properties, and energy transfer pathways. Synthesized ethynyl-functionalized triarylborane derivatives exhibit pronounced aggregation-enhanced circularly polarized luminescence (CPL), with dissymmetry factors |g_lum| reaching 10^–3 in thermally annealed films, significantly higher than those in solution. Notably, they undergo reversible photoinduced crystalline assembly under 365 nm UV irradiation and serve as sensitive fluoride-ion sensors via reversible B–F coordination. When doped into a triphenylamine host matrix, the systems display remarkably stable room-temperature phosphorescence with lifetimes exceeding 200 ms and visible yellowish-green afterglow, accompanied by clearly detectable CPL activity. The representative compound R/S-CHTAB can be fabricated into a binary doped film system with the achiral acceptor rhodamine B (RB), which realizes efficient FRET and excited-state chirality transfer, affording widely tunable emission color and CPL signals. Furthermore, we constructed a ternary host–guest complex system by integrating this binary system with the triphenylamine host matrix, and achieved wide-spectrum color-tunable long-lived phosphorescence emission from green to orange-red via a cascaded triplet energy transfer process.