Red Upconversion Emission Of Er3 Research Articles

A New Blue, Green and Red Upconversion Emission Nanophosphor: BaZrO3:Er,Yb

Strong Blue, green, and red upconversion emission of Er3+ in nanocrystalline BaZrO3:(Yb3+Er3+) is observed. Powder samples were obtained by a facile hydrothermal process at 100 degrees C. The as synthesized nanocrystallites preserve a stable cubic perovskite phase under subsequent annealing treatment up to 1000 degrees C. No other phase or segregation of other compounds was detected. Crystallites sizes were around 115 nm and well faceted. Under IR excitation in the range between 900 and 1050 nm the Er3+ blue emission was almost not present in single Er3+ doped BaZrO3, whereas it became easily observable when Yb3+ was added as codopant. Besides, both green and red upconversion emission or upconverted signal of Er3+ are enhanced by around three orders of magnitude in comparison with the single Er3+ doped BaZrO3. The strong blue emission presents dependence on both excitation power and excitation wavelength. This is the first time that upconversion emission is observed in BaZrO3. A possible mechanism for the upconversion process that leads to the observed blue, green and red emissions under NIR excitation is suggested based on the experimental results.

Green and red upconversion emissions of Er3+/Yb3+-codoped SrTiO3 powder prepared by a polymeric precursor method

Ultrafine Er3+/Yb3+-codoped SrTiO3 (SEYT) powders in cubic form have been prepared by a poly-meric precursor method. The single phase perovskite for the obtained material was observed at low temperature. An efficient infrared-to-visible conversion in SEYT perovskite will be reported. Visible emissions at 550 and 663 nm corresponding to the 2S3/2 − 4I15/2 and 4F9/2 − 4I15/2 transitions, respectively, were observed under continuous wave excitation at 980 nm. An enhancement of the visible upconversion luminescence in Er3+/Yb3+ codoped samples was confirmed due to efficient energy transfer from Yb3+ to Er3+ ions. The quadratic pump power dependence of these emissions indicated the contribution of two photons to the upconversion process.