Modulation of a solid-state reversible fluorescent photoswitching based on a controllable photochromic pyrazolones

摘要

A novel solid-state reversible fluorescence photoswitching system (FPS) based on photochromism of photochromic pyrazolones has been developed by employing phosphor Sr_2P_2O_7 co-doped with europium ion and chlorine ion (Sr_2P_2O_7-EC) and 1,3-diphenyI-4-(3-chlorobenzaI)-5-hydroxypyrazole-4-phenylsemicarbazone (la) as the fluorescence dye and the photochromic compound, respectively. With carefully selected components, the absorption band of the keto-form photochromic pyrazolones well overlaps with the emission peak of Sr_2P_2O_7-EC. The fluorescence emission intensity of Sr_2P_2O_7-EC is efficiently modulated by the photoisomerization of la with controlling the exposure time in the solid state. The fluorescence photoswitching system displayed high fluorescence quenching efficiency and remarkable fatigue resistance. It can be repeated 7 cycles without observable the changes of emission intensity. A fluorescence quenching efficiency can be achieved with a reversible colour change from white to yellow.