Interfacial Charge-Transfer States in Organic Cocrystals: Characterization and Excited-State Dynamics

Organic charge-transfer (CT) cocrystals with ordered donor–acceptor (D–A) arrangements have emerged as promising materials for optoelectronic applications. Elucidating interfacial CT-state dynamics is essential for correlating intermolecular D–A interactions with macroscopic material functionalities. Enabled by the advanced steady-state and time-resolved spectroscopies, extensive studies have been devoted to exploring CT-related photophysical processes in organic cocrystals, including CT-state formation, radiative recombination, spin conversion, energy transfer, and exciton migration. In this Review, we systematically summarize the fundamental characteristics of CT states and present representative spectroscopic strategies for investigating their properties in both photophysical and photodynamical aspects. Key challenges and future perspectives are further highlighted toward precise kinetic regulation and dynamics-guided material design. By bridging interfacial D–A interactions, CT-state dynamics and functional performance, this Review aims to provide a fundamental framework for advancing CT-related photophysics and facilitate the development of high-performance organic optoelectronic CT cocrystals.