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

• A solid-state fluorescence photoswitching material was prepared.
• Photoswitching is due to energy transfer between pyrazolone and fluorescence dye.
• It exhibits excellent fluorescence contrast and fatigue resistance in the solid state.

A novel solid-state reversible fluorescence photoswitching system (FPS) based on photochromism of photochromic pyrazolones has been developed by employing phosphor Sr2P2O7 co-doped with europium ion and chlorine ion (Sr2P2O7–EC) and 1,3-diphenyl-4-(3-chlorobenzal)-5-hydroxypyrazole-4-phenylsemicarbazone (1a) 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 Sr2P2O7–EC. The fluorescence emission intensity of Sr2P2O7–EC is efficiently modulated by the photoisomerization of 1a 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.

A novel fluorescence photoswitching system based on doping inorganic fluorescence dye into photochromic pyrazolones was constructed successfully. Its fluorescence emission could be efficiently modulated by the photoisomerization of pyrazolones.Figure optionsDownload as PowerPoint slide