Rare-earth ions in porous matrices

Initially motivated by the commercial need for cheaper and environmentally friendly luminescent materials for application in fluorescent lamps and cathode ray tubes, the search for new matrices for optically active species has penetrated a scope far beyond “classical” solid-state materials. Porous matrices with voids ranging from the nano-to the microscale have become the subject of recent investigations. Crystalline, amorphous, organomorphous, nanosized matrices and matrices, which are amorphous on the atomic level but have a translational superstructure on the microscale (zeolites, sol-gel materials, polymers, nanoparticles and photonic crystals), are addressed. The optical technologies covered in this research range from mercury free discharge lamps, plasma displays, organic and polymeric light emitting diodes, and novel laser materials to biophotonics and the new generation of white emitting AlGaN solid-state light emitting diodes (LEDs). Due to their specific properties (e.g., high quantum yields, narrow line emission), rare-earth ions are indispensable components of these approaches, be it in the nanoscaling zeolites, sol-gel matrices, or as the active component in optically functional polymers. Optical properties of hybrid materials composed of either rare-earth ions as such, their complexes, or nanoparticles in these matrices, with potential application in the fields mentioned, will form the scope of the present report.