Athermal photofluidization of glasses

作者：Fang G J; Maclennan J E; Yi Y; Glaser M A; Farrow M; Korblova E; Walba D M; Furtak T E; Clark N A^*

来源：Nature Communications, 2013, 4(1): 1521.

DOI：10.1038/ncomms2483

Azobenzene and its derivatives are among the most important organic photonic materials, with their photo-induced trans-cis isomerization leading to applications ranging from holographic data storage and photoalignment to photoactuation and nanorobotics. A key element and enduring mystery in the photophysics of azobenzenes, central to all such applications, is athermal photofluidization: illumination that produces only a sub-Kelvin increase in average temperature can reduce, by many orders of magnitude, the viscosity of an organic glassy host at temperatures more than 100 K below its thermal glass transition. Here we analyse the relaxation dynamics of a dense monolayer glass of azobenzene-based molecules to obtain a measurement of the transient local effective temperature at which a photo-isomerizing molecule attacks its orientationally confining barriers. This high temperature (T-loc similar to 800 K) leads directly to photofluidization, as each absorbed photon generates an event in which a local glass transition temperature is exceeded, enabling collective confining barriers to be attacked with near 100% quantum efficiency.

• 出版日期2013-2