Femtosecond dynamics of IR molecules in hybrid materials

We report on the optical properties of two dye molecules absorbing in the near infrared region (0.8-1.1 mum) and emitting up to 1.3 mum. The chromophores are embedded in hybrid organic/inorganic silicon-based films synthesized by a modified sol-gel technique. Femtosecond time-resolved emission spectra have been measured in order to determine the effect of the solid cage on the excited state dynamics of the trapped molecules. For comparison, measurements in different solvents are reported and an estimation of the relative quantum efficiency in solid glassy material with respect to liquid solutions is given. Measurements are discussed in terms of physical and chemical interactions with the host matrix. (C) 2001 Elsevier Science B.V. All rights reserved.