Solidification and Simultaneous Dual-Wavelength Emission of Rhodamine 6G and Coumarin 102 Codoped in AlPO₄ Mesoporous Glass

Abstract

Transparent AlPO4 mesoporous glasses codoped with different amounts, as well as different molar ratios, of Rhodamine 6G (Rh6G) and Coumarin 102 (Cou102) were fabricated by a dipping method. Solidification of dyes in mesoporous AlPO4 glasses was probed by 27Al and 31P solid state NMR techniques. The interaction of dyes with the glassy AlPO4 network has been characterized by a new six-coordinated aluminum species (Al(6)) environment in 27Al MAS spectra, combined with advanced solid state NMR techniques probing 27Al−1H and 27Al−31P internuclear dipole couplings. Optical excitation and simultaneous dual-wavelength emission spectra of both series of samples show significant dependences on the Rh6G and Cou102 concentration and Cou102/Rh6G molar ratio. Efficient simultaneous dual-wavelength emission was observed at low dye concentration (<10−5 M), whereas at high dye concentration (>10−3 M), quenching of the fluorescence of Cou102 happened, but the fluorescence intensity was dependent on the Cou102/Rh6G molar ratio.