Zhang Baowen

Photoinduced electron transfer of [ Ru (bpy)2 (4,4′‐dcbpy) ]2+ with electron donors

Emission quenching of [Ru(bpy)2(4, 4’-dcbpy)] (PF6)2 (1) by benzenamine,4-[2-[5-[4-[4-dimethylamino]phenyl]-4,5-di-hydro-1-phenyl-1H-pyrazol-3-yl]-ethenyl]-N,N-dimetyl (2) or 1, 5-diphenyl-3-(2-phenothiazine)-2-pyrazoline (3) was observed. Measurements of the emission decay of 1 before and after addition of 2 or 3 by single photon counting technique con-finned the observations. The emission quenching of 1 by 2 or 3 was submitted to Stern-Volmer equation. It was calculated that the quenching rate constants (kq) are 5.5 × 109(mol/L)-1s-1 for 2 and 4.0 × 109(mol/L)-1s-1 for 3, respectively. These results indicated a character of dynamic quenching process. The singlet-state of 2 or 3 was also quenched by 1. The quenching behaviors did not conform to the Stern- Volmer equation and involved both static and dynamic quenching processes. The apparent quenching rate constant (kapp) was calculated to be 3 × 109 (mol/L)-1 for the interaction of excited 2 with 1, and 1.2 × 109 (mol/L)-1 for that of excited 3 wit

A New Photorefractive Polymer with Fast Response

Photorefractivity properties of a polymer are investigated by four-wave mixing (FWM) diffraction measurements. The polymer is composed of photoconducting poly (n-vinylcarbazole), photosensitizing 2,4,7-trinitro-9-fluorenone, and optically nonlinear 4-(dicyanovinyl)-N. N-diethylaniline. Its FWM diffraction efficiency and response time as a function of, respectively, electric field and writing intensity have been determined. With a 80 μm-think film, a diffraction efficiency of 7.4 × 10-4 has been obtained. The response time of the polymer is as short as 400 ms at a writing intensity of 0.17 W/cm2.