화학공학소재연구정보센터
Applied Surface Science, Vol.478, 412-416, 2019
Infrared-laser precipitation of Dy3+-Yb3+ codoped SrF2 nanocrystals in glass and upconversion luminescence
Oxyfluoride glass-ceramics containing SrF(2)nanocrystals have been prepared by a CO2 laser treatment on the glass prepared by high temperature melt quenching. The optimized scan speed and laser power produced nanocrystals with sizes of similar to 10 nm. Energy dispersive spectroscopy mapping analysis showed that Dy3+ and Yb3+ ions are highly populated inside the SrF2 nanocrystals. We also report a substantially enhanced down-converted visible emission from the 4F9/2 state of Dy3+ ions, including some violet emissions from the higher energy states under 365 nm excitation in the glass-ceramics, as compared to the as-made glass. Moreover, 980 nm laser diode excitation produced strong green and red emissions from the I-4(15/2) state and blue and yellow emissions from the F-4(9/2) state. A model has been proposed to interpret the upconversion emissions through the multistep-excitation of Dy3+ ions and energy transfers from, efficient sensitizers, Yb3+ ions to Dy3+ ions.