作者：Hao Ya-Wei; Wang Hai-Yu; Huang You-Ju; Gao Bing-Rong; Chen Qi-Dai; Li Liang-Bin; Sun Hong-Bo*
关键字：molecular switching of azobenzene
论文来源：期刊
具体来源：J. Mater. Chem. C, 2013, 1, 5244–5249
发表时间：2013年
The excited state relaxation of two types of azobenzene derivative excited at 350 nm in the short-wavelength (S2([small pi], [small pi]*)) band was studied by transient absorption spectroscopy. We compared the relaxation dynamics and the time-resolved anisotropic relaxation properties of these two molecules in liquid solution and in bulk film. The average relaxation life-time for Azo-2 in bulk film (13.2 ps) is much slower than that of Azo-2 (4.06 ps) and Azo-1(1.31 ps) in liquid solution. The time-resolved polarization anisotropy spectroscopy measurements of these samples also showed significant differences. The value of anisotropy for Azo-2 remained almost constant at about 0.2 in bulk film but decayed slowly from 0.3 in liquid solution. The value for Azo-1 in liquid solution decayed very fast from 0.4 to 0.2 within 6 ps. Our results gave new evidence for the existence of a converted inversion channel. We also concluded that the concerted inversion process and the conventional rotation process govern the relaxation for the photon-induced switches of azobenzene and its derivatives under short-wavelength band excitation.