Study of optical properties and up-conversion mechanism in Nd3+/Yb3+ ions co-doped SiO2-Al2O3-Na2CO3-SrF2-CaF2 glasses for green light emitting display device applications

摘要

The oxyfluorosilicate glasses with the composition of (44-x)SiO2 + 5Al(2)O(3) + 17 Na2CO3 + 18SrF(2) + 15CaF(2) + 0.5Nd(2)O(3) + xYb(2)O(3) (x = 0.1, 0.5, 1.0 and 2.0 mol %) have been prepared by conventional melt quenching technique. The optical absorption, emission and up conversion spectra were carried out. The strong absorption peak observed at 804 nm corresponding to the transition I-4(9/2) - F-4(5/2) + H-2(9/2). The emission spectra were recorded for Nd3+ singly and Nd3+/Yb3+ co-doped glasses with 808 nm laser diode as an excitation source. For the present investigation, the glass co-doped with 0.5 Nd3+, 0.5 mol% Yb3+ ions have the highest emission intensity. PL up-conversion (UC) emission have been analysed under the excitation of 980 nm laser diode. It is observed that four intense up-conversion emission bands at around 500 tun, 537 nm, 596 nm and 662 nm ascribed to the electronic transitions (4)G(9/2) - I-4(9/2), (4)G(7/2) + K-2(13/2) - I-4(9/2), (4)G(5/2) + (2)G(7/2) - I-4(9/2) and (4)G(7/2) + K-2(13/2) - I-4(13/2) respectively. The green emission band at 500 rim ((4)G(9/2) - I-4(9/2)) has the highest peak intensity for 0.5 mol % Nd3+ and 2.0 mol % Yb3+ ions co-doped glass. For the present work the values for n = 1.76, 1.93 and 2.25 for UC emission at 500, 596, 662 nm respectively. The value n approximate to 2 suggesting that two photons are involved in the UC process of present glass system. The above results suggesting that the prepared glasses co-doped with Nd3+/Yb3+ ions may be used for green light emitting display device applications.