Ultrafast Dynamics in Multibranched Structures with Enhanced Two-Photon Absorption

摘要

Organic materials with strong two-photon absorption (TPA) properties have motivated the creation of new photonic devices.Significant enhancement of the TPA cross-section in multibranched structures has been reported.The enhanced TPA properties have been theoretically investigated,and the importance of charge-transfer character and excitation delocalization has been shown.Previously,time-resolved spectroscopic studies have been used to probe the mechanism of the enhancement.However,the basic structure-function relationships regarding excited-state dynamics (transition moments,electronic coupling between levels,interaction with solvent) and enhanced TPA properties remain unclear.To further understand this important issue,a systematic set of branched chromophore systems that demonstrate the enhanced TPA properties were investigated using a combination of time-resolved spectroscopic techniques.