.Effect of Yb3+ concentration on Er3+ luminescence properties of sol-gelderived silica-alumina xerogels[J].Optoelectronics Letters,2006,2(5):354-357 Effect of Yb3+ concentration on Er3+ luminescence properties of sol-gelderived silica-alumina xerogels K.Tran Ngoc H. Pham Thanh C. Nguyen Duc C. Armellini A. Chiaserat M. Ferrari Y. Jestin M. Montagna E. Moser S. Pelli G.C. Righini [1]CNR-IFN Istituto di Fotonica e Nanotecnologie , CSMFO group, via Somrnarie 74,1-38050 Povo, Trento, Italy [2]ITIMS-Hanoi University of Tecl~ology, No 1, Dai Co Viet, Hanoi, Vietnam [3]Dipartimento di Fisica, Universita di Trento, CSMFO group, via Sommarive 74,1-38050 Povo, Trento, Italy [4]CNR-IFAC Nello Carrara Institute of Applied Physics, Lab. of Optoelectronic Technologies, Via Madonna del Piano70,50079 Sesto Fiorentino, Firenze, Italy Abstract:       Er3+ / Yb3+ co-doped silica-alumina monolithic xerogels were prepared with the same concentration on 2 000 Er/Si ppm and 6 000 Al/Si ppm. The Yb/Si content was varied from 0 to 4 000 ppm Densification of the samples was achieved by thermal treatment in air at 950 °C for 120 hours with a heating rate 0.1 °C/min. Photoluminescence spectroscopy was used to obtain information about the effective excitation efficiency of Er3+ ions by co-doping with Yb3+ ions. The infrared-to-visible up-conversion luminescence has been investigated upon continuous wave excitation at 980 nm. The samples exhibit red, green and blue up-conversion emission. It is found that the intensity of up-conversion luminescence increases with increasing Yb3+ doping concentration. An opposite behavior is observed for the4l13/2 luminescence of the Er3+ ions. This research is performed in the context of the Italy-Vietnam research project 6 BS 2 MAE 2006–2008. MIUR-FIRB RBNE012 N3X, PAT FAPVU2004–2006, MIUR-PRIN 2004–2006. Hits: 3580 Download times: 177 View Full Text    Download reader