Enhanced green emission from Er2WO6 nanocrystals embedded composite tellurite glasses

A series of tungsten-tellurite glasses activated with different concentrations (0-1.5 mol%) of Er(3+) has been synthesized. The structural properties of the best luminescent sample and the optical properties of its Er(3+) ions, are studied both immediate after its preparation as well as after its ageing. On ageing the glass suffers structural reorganization and generates Er(2)WO(6)-nanocrystals in the matrix, which greatly enhances the normal and upconversion green luminescence efficiency of Er(3+). The nanocrystal aided enhancement of normal and upconversion luminescence of Er(3+) of the glass has been attributed to the crystal field effects of the new environment of Er(3+) in the nanocrystals. A phenomenon of preferential enhancement of red upconversion luminescence at the cost of green upconversion luminescence of Er(3+) at its higher concentrations in the glass has been observed and the related photo-physics is proposed. The material shows the prospect of being used as NIR solar concentrator.