Linear and nonlinear luminescence properties of thiophene based materials

Three new thiophene based organic luminescence compounds, i.e., 2,5-bis(4'-N,N-di- methylaminostyryl)thiophene (BMST), 2,5-bis(4'-N,N-diethylaminostyryl)thiophene (BEST) and 2,5-bis(4'-N-cyclobutylaminostyryl)thiophene (BBST), were synthesized. All of their measured single-photon excited fluorescence (SPEF) are located in the range of 530 nm with quantum yields of around 40 %, and the corresponding lifetime was 1n s. The ex- amined compounds show strong solvatochromism in their SPEF spectra. Excited by a fs laser at 800 nm, a strong up-converted fluorescence of the examined compounds was de- tected. The profile of two-proton excited fluorescence (TPEF) was similar to that of SPEF. The two-photon absorption (TPA) cross sections of the compounds were determined by the TPEF method. All the compounds showed large TPA cross sections. Hence these thiophene derivatives may have good TPA properties.