Energy-migration-assisted vibrational quenching at mesoscale phosphor-polymer interfaces

Interactions at luminescent particle-organic interfaces are spatially confined to the particle boundary, yet whether their energetic influence can extend beyond this localized region remains unclear in mesoscale particle systems. We hypothesize that internal excitation-energy migration connects particle excited states to localized interfaces, enabling microscopic interfacial dissipation to exert energetic effects beyond its immediate spatial range.

SrAl₂O₄:Eu²⁺,Dy³⁺ (SAOED) was used as a mesoscale model to construct solid and liquid particle-organic interfaces with distinct vibrational environments. CHCl₃/CDCl₃ isotope controls were employed to probe molecular-vibration effects. Time-resolved spectroscopy, together with systematic variation of Eu²⁺ concentration and particle size, was used to examine the coupling between interfacial energy dissipation and internal energy migration.

External vibrations are correlated with interfacial nonradiative dissipation, with stronger or higher-energy vibrations producing greater luminescence attenuation and shorter excited-state lifetimes. The direct influence of external molecular vibrations remains largely localized at the particle-organic interface, whereas internal energy migration links particle excited states to this localized dissipation region. The consistency of this behavior across different systems further suggests that the interfacial vibrational environment is a broadly relevant interfacial variable and supports a cross-scale principle: localized interfacial interactions at the microscopic scale can, through internal energy transport, generate energetic consequences at larger length scales.