Steady and transient behavior of perylene under high pressure

Pressure can reduce the distances among atoms, thereby modifying the overall optical characteristics of molecules. In this article, the excited state behavior of perylene is carefully observed under isotropic pressure and non-complexing condition. In a steady state, absorption peak shows red shift and spectral width are broadened with pressure increasing, which is ascribed to the π-electron delocalization between molecules. In a transient state, the transition dynamics presents a wavelike tendency with pressure increasing because the shift of self-tapping exciton state is contrary to that of Y-state with pressure increasing. The results conduce to understanding the influence of inter-molecule interaction on excited state behavior with inter-molecule distance decreasing, which contributes to studying the materials under extreme condition.     

Investigation of fluorescence resonance energy transfer ultrafast dynamics in electrostatically repulsed and attracted exciton-plasmon systems

Following the gradual maturation of synthetic techniques for nanomaterials,exciton-plasmon composites have become a research hot-spot due to their controllable energy transfer through electromagnetic fields on the nanoscale.However,most reports ignore fluorescence resonance energy transfer(FRET)under electrostatic repulsion conditions.In this study,the FRET process is investigated in both electrostatic attraction and electrostatic repulsion systems.By changing the Au:quantum dot ratio,local-field induced FRET can be observed with a lifetime of ns and a fast component of hundreds of ps.These results indicate that the intrinsic transfer process can only elucidated by considering both steady and transient state information.