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           COLLOQUIUM OF THE COMPUTATIONAL MATERIALS SCIENCE CENTER
                              College of Science
                       (CDS Department CSI 898-Sec 001)
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 Vapor Phase Synthesis of Upconverting  Nanocrystals to Generate Red, 
                Green, Blue and White Light

                     Garry P. Glaspell
Department of Chemistry, Virginia Commonwealth University, Richmond, VA

We report, for the first time, the vapor phase synthesis of upconverting 
Y2O3 nanocrystals doped with Yb3+, Er3+, Ho3+ and Tm3+ to generate red, 
green, blue and white light. Incorporating Er3+ within the Yb3+-doped 
Y2O3 nanocrystals under the 980 nm laser excitation produces orange 
and yellow upconversion luminescence tunable by varying the Yb3+ 
concentration. The Yb3+, Er3+ and Tm3+-codoped Y2O3 nanocrystals 
exhibit nearly equal intensities of the red, green and blue emissions 
upon the 980 nm laser excitation. White light can be produced by 
adjusting the concentrations of the Ln3+ ions within the Y2O3 
nanocrystals.


                        Monday, September 15, 2008
                                  4:30 pm
                     Room 301, Research I, Fairfax Campus

Refreshments will be served at 4:15 PM.
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Find the schedule at www.cmasc.gmu.edu/seminar/schedule.html
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