PDF Publication Title:
Text from PDF Page: 081
Rare Earth-Doped Phosphors for White LEDs Chapter 278 45 1 ex. em 0.5 0 300 400 500 600 700 Wavelength (nm) Excitation and emission spectra of La3Si6N11:Ce3+. Redrawn from Seto, T., Kijima, N., Hirosaki, N., 2009. A new yellow phosphor La3Si6N11:Ce3+ for white LEDs. ECS Trans. 25, 247–252. reddish–yellow emission band with peaks at 525 and 595 nm. The external quantum efficiency of the phosphor is 42% under an excitation at 450 nm. With increasing temperature up to 150°C, the emission intensity decreases by about 28% with respect to that at 25°C, owing to thermal quenching; this is a little less than for YAG:Ce3+. Then, the thermal stability against temper- ature quenching is lower compared with another yellow-emitting (oxy)nitride phosphors such as Ca-a-SiAlON:Eu2+ and CaAlSiN3:Ce3+. 4.2.2 Blue-Emitting Phosphors 4.2.2.1 Y2Si3O3N4:Ce3+ Phosphors The crystal structure and luminescence properties of the Y–Si–O–N quaternary system have been studied (Ching et al., 2004; Deng et al., 2011; Katharine and Derek, 2001; Lu et al., 2010, 2011; van Krevel et al., 1998, 2000, 2001; Wang and Werner, 1997; Xu et al., 2005; Yang et al., 2015). Among these quaternary materials, Ce3+-activated Y2Si3O3N4 is known to exhibit a blue emission under near-UV excitation (Lu et al., 2011; van Krevel et al., 1998, 2000). Fig. 43 illus- trates the crystal structure of Y2Si3O3N4 that crystallizes in an N-melilite-type tetragonal structure with space group P421m, a1⁄40.7614 nm, c1⁄40.4915 nm, and V1⁄40.2849 nm3 (Lu et al., 2011). The Y3+ ions occupy a crystallographic site and adopt eightfold coordination being bound to four oxygen and four nitrogen atoms; the average Y–N/O bond distance amounts to 0.2514 nm (van Krevel et al., 2000). The optimum concentration of Ce3+ in Y2Si3O3N4:Ce3+ was found to be (Y0.98Eu0.02)2Si3O3N4 (Lu et al., 2011). This phosphor shows two broad FIG. 42 Normalized intensity (a.u.)PDF Image | HANDBOOK ON THE PHYSICS AND CHEMISTRY OF RARE EARTHS
PDF Search Title:
HANDBOOK ON THE PHYSICS AND CHEMISTRY OF RARE EARTHSOriginal File Name Searched:
Chemistry-Rare-Earths-49.pdfDIY PDF Search: Google It | Yahoo | Bing
Sulfur Deposition on Carbon Nanofibers using Supercritical CO2 Sulfur Deposition on Carbon Nanofibers using Supercritical CO2. Gamma sulfur also known as mother of pearl sulfur and nacreous sulfur... More Info
CO2 Organic Rankine Cycle Experimenter Platform The supercritical CO2 phase change system is both a heat pump and organic rankine cycle which can be used for those purposes and as a supercritical extractor for advanced subcritical and supercritical extraction technology. Uses include producing nanoparticles, precious metal CO2 extraction, lithium battery recycling, and other applications... More Info
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)