Vibrational-State-Regulated Hot-Band Thermal Activation for Anti-Stokes Luminescence

Thermal-vibrational-activation-dominated hot-band absorption (HBA) is a key mechanism for achieving anti-Stokes luminescence, utilizing environmental thermal energy to enable photon emission at energies higher than absorption. The HBA necessitates thermal vibrational activation (υ = 0 → 1), which remains a challenging yet critical task in molecular design. This study presents a molecular design strategy integrating a multi-resonance core with tailored peripheral groups. Through the modification of the surrounding groups, the vibrational modes that contribute to the thermal vibrational activation can be modulated. The mechanism of the thermal vibrational activation is elucidated by distinguishing the roles of the resonance core and peripheral groups in governing low- and high-energy vibrational modes, respectively. Based on statistical mechanics, a theoretical approach is proposed to analyze the contribution of each vibrational mode. A structure-property relationship is established for HBA systems, providing a foundational framework for the development of advanced anti-Stokes luminescent materials.