Effects on the Two-photon Excited Fluorescence of Thiophene Derivatives

Guang-Ming Xia,* Ping Lu, and Shi-Quan Liu
School of chemistry and chemical engineering, Jinan University, Jinan 250022, P. R. ChinaE-mail: xiagm2008@163.com

Three new thiophene-based organic luminescence compounds named as 2,5-bis(p-N,N-diethylaminostyryl)thiophene (BEST), 2,5-bis(p-N,N-diphenylaminostyryl)thiophene (BPST) and 2,5-bis(p-N-carbazoylstyryl)thiophene (BCST) were synthesized. All of their single-photon excited fluorescence (SPEF) locate in the range of ~530nm with the quantum yield around 40%, and the corresponding lifetime was ~1 ns. The target compounds show strong solvatochromism in their SPEF spectra except BCST. There is no obvious change for the peak wavelength in the linear spectra of BCST in different polar solvent. Excited by a fs laser at 800 nm, strong up-converted fluorescence of target compounds was detected. The profile of two-photon excited fluorescence (TPEF) was likely with that of SPEF. The two-photon absorption (TPA) cross sections of the compounds were determined by TPEF method. All target compounds show large TPA cross section in our experiments. So that thiophene derives may have good TPA properties. 

Key words: two-photon absorption, up-converted fluorescence, thiophene derivatives