4th SmoleQ Greeting Seminar (2025.01.20 at 17:00 (JST))

 

Speaker: 

Po-Chen Kuo

Title: 

Dissipative engineering of environments for optimized photo-oxidation suppression in organic chromophores

Abstract:

This work addresses the critical challenge of dye molecule oxidation and  its impact on device stability by investigating the suppression of  photobleaching through engineering the chromophore's surrounding  environment. We induce strong coupling with confined light modes  [optical cavities or localized surface plasmons (LSPs)] to reduce the  triplet state population, thereby mitigating photo-oxidation. Utilizing  the hierarchical-equations-of-motion (HEOM) approach to capture  non-Markovian and non-perturbative effects, we analyze both  cavity-chromophore and LSP-chromophore systems. Our analysis reveals  that the optimal antioxidation performance depends on the competition  between cavity-chromophore coupling and cavity-bath (dissipation)  interaction. Importantly, in the strong cavity-chromophore coupling  regime, increasing cavity dissipation can enhance antioxidation through  quantum coherence-induced population transfer. Conversely, in the weak  cavity-chromophore coupling regime, increasing cavity dissipation can  counterintuitively reduce the antioxidation capability due to a quantum  Zeno-like effect. Furthermore, in the LSP-chromophore system,  engineering the LSP structure, particularly the LSP dissipation rate,  can similarly be used to optimize the antioxidation effect. These  findings, complemented by analytical results for finding optimal system  parameters, provide practical guidelines for designing photostable  organic materials with enhanced performance in various optoelectronic  applications.