Enhanced two-photon absorption and ultrafast dynamics of a new multibranched chromophore with a dibenzothiophene core.
A series of novel compounds with dibenzothiophene core branched structures have been synthesized, and their two-photon absorption (TPA) properties were investigated. Two-photon fluorescence (TPF) and z-scan techniques were carried out, and a significant enhancement in the TPA cross section was observed for ST-G2, which possesses the largest generation number among the studied samples. By using different solvents, the largest nonlinear optical (NLO) response was observed in the most polar solvent. Ultrafast pump-probe experiments were performed to probe the excited state dynamics in the branched molecules, and the obtained results further confirmed the TPA enhancement mechanism. Time-resolved fluorescence (TRFL) and TRFL anisotropy measurements reveal that there is an ultrafast charge localization to the intramolecular charge transfer (ICT) state followed by relaxation with a lifetime longer than 1 ns.
Yan
Yongli
Y
Physics Department, Fudan University, Shanghai 200433, People's Republic of China, Surface Physics Lab (National Key Lab), Fudan University, Shanghai 200433, People's Republic of China.
Li
Bo
B
Liu
Kangjun
K
Dong
Zhiwei
Z
Wang
Xiaomei
X
Qian
Shixiong
S