Influence of Er3+ on structural and optical properties of borophosphate glasses.

This paper reports the physical, structural, optical and luminescence properties of Er 3 + doped borophosphate glasses. The samples were prepared with melt quenching technique at 1250 ∘ C by varying the concentration of Er 2 O 3 from 0.1 to 0.5 mol%. Density is measured by Archimedes principle and variation in density with erbium's concentration established its participation in the glass structure. X-ray diffraction affirmed the amorphous nature of the prepared glasses. Fourier transform infrared spectroscopy spectra revealed the structural units such as P--O--P , B--O--B and BO 4 present due to stretching and bending vibrations of various bonds. Ultra-violet-visible absorption spectra displayed various absorption peaks/bands originating from ground state of erbium 4 I 15 / 2 to 2 K 15 / 2 , 4 G 9 / 2 , 4 G 11 / 2 , 2 G 9 / 2 , 4 F 5 / 2 , 4 F 7 / 2 , 2 H 11 / 2 , 4 S 3 / 2 and 4 F 9 / 2 . The indirect optical band gap values varied between 2.56 and 3.19 eV. Judd Ofelt parameters ( Ω 2 , Ω 4 , Ω 6 ) were evaluated and they followed Ω 2 > Ω 4 > Ω 6 trend. These parameters helped to calculate radiative transition probability, stimulated emission cross section and gain bandwidth. For luminescence studies, the glass samples were excited at 379 nm and emission occured in the visible region showing peaks at 405 nm, 485 nm and 517 nm. Commission International de I'Eclairage (CIE) coordinates (x and y) were calculated for the glass samples and these coordinates lie in the blue region of CIE chromaticity diagram. [ABSTRACT FROM AUTHOR]