Colour tuneable emission from (Y1.995−xGax)2O3:Bi3+ phosphor prepared by a sol-gel combustion method

The (Y1−xGax)1.995O3:Bi0.005 [x=ranging from 0.0 up to 1.0 with steps of 0.1] phosphor samples have been prepared using a sol-gel combustion method. The variation of the composition on the photoluminescence (PL) properties of these samples has been investigated. The colour tuneable emission was obtained as a result of an increase of the Ga concentration in the (Y1−xGax)1.995O3 host matrix from 0.0 up to x=0.8. No emission was observed for the x=0.9 and 1.0 which was ascribed to the spectral overlap between the 3P1 excitation band and the conduction band of the host. A systematic emission colour tuneability from blue-green to purple, shifting in the excitation bands to shorter wavelengths, a variation in the PL intensities as well as different stokes shifts were observed.