Formation of fluorescent aggregates in Rhodamine 6G doped silica glasses

The photoluminescence properties of type I sol–gel synthesized Rhodamine 6G doped silica samples were investigated in the 1.5 × 10−4–1.5 × 10−3 mol/l range of concentration by means of steady-state and time resolved photoluminescence measurements. The emission peak red shifts as the concentration increases. For a fixed concentration, the peak position also red shifts as the excitation wavelength decreases. The observed spectroscopic features, including excitation of photoluminescence and decay time, indicate the formation of fluorescent dimers.