Concentration-dependent luminescent behaviour of Rhodamine 6G in AlPO4 xerogel monoliths

Homogeneous monolith of AlPO4 gel doped with Rhodamine 6G (Rh6G) in different dye concentration is prepared by one step process with sol–gel method using the precursors Al(lact)3 and H3PO4. The optical properties of AlPO4 gel doped with Rh6G have been characterized by UV–vis absorption spectra and fluorescence spectra. Rh6G molecular J-dimers and H-dimers even multimers are analyzed by excitation spectra based on Exciton theory. The structure of AlPO4 gel doped with Rh6G is investigated by 27Al and 31P Magic Angle Solid Nuclear Magnetic Resonance (MAS NMR), 27Al {31P} Rotational Echo Double Resonance (REDOR) NMR and 27Al Triple Quantum Magic Angle Spinning (TQ-MAS) NMR. Based on the results of optical spectra and the structural analysis by NMR techniques, The AlPO4 gel doped with Rh6G dye with molar ratio of Rh6G/Al(lact)3 of 1 × 10−4 displays excellent optical properties.