Cerium-ion-doped yttrium aluminum garnet nanophosphors prepared through sol-gel pyrolysis for luminescent lighting

Abstract

Luminescent Y3Al5O12: Ce3+ [yttrium aluminum garnet (YAG):Ce3+] nanoceramics (5–50 nm) have been prepared through a facile sol-gel pyrolysis route. A blueshift of about 720 cm−1 in the reflectance spectra near the absorption edge can be observed for YAG:Ce3+ nanoparticles (having an average particle size around 5 nm) with respect to the submicron powders (∼0.9 μm). Furthermore, the scope of application for this important luminescent system can be extended by isostructural substitution with heavier cations such as Ba2+. This substitution giving rise to an oxygen-vacancy defect complex, that exhibits certain size-sensitive exciton-impurity energy-transfer property in YAG:Ce3+ nanoparticles.

Glycothermal synthesis and photoluminescence of YAG:Ce3+ nanophosphors

“…YAG:Ce 3+ phosphor is produced by conventional solid-state reaction at 1100-1400 • C [1,2]. Lower temperature syntheses, such as spray-pyrolysis [3,4], co-precipitation [5,6], sol-gel processing [2,[7][8][9][10][11] and hydrothermal method [12,13] have been reported.…”

Large anomalies due to insufficiency of Madelung embedding inab initiocalculations of4f−5dand4f−6sexcitations

“…[1][2][3][4] These states have been the subject of experimental studies for many years and their understanding is mainly supported by semiempirical models. [5][6][7] Theoretical methods based on the first principles might deliver significant contributions in this respect for two reasons: First, because they can provide sound analyses of interactions and effects involved in the processes, 8 and, second, because ab initio calculations that do not rely on empirical information can nowadays successfully simulate 4f-5d electronic spectra, 9 not only absorption spectra but also emission spectra.…”

Efficient energy transfer between nanocrystalline YAG:Ce and TRITC

“…Intermittence in emission (blinking), which is a problem in certain applications of single quantum dots, is not expected for inorganic phosphor nanocrystals as they contain a large number of luminescing ions (typically between 10 and 10 000 depending on the size of the nanocrystal and the concentration of luminescing ions). In the past few years there has been a growing interest in the properties of nanocrystalline lanthanide-doped insulating phosphors, and several well-known materials, such as Y 2 [15][16][17][18][19] ), have been prepared in nanocrystalline form. The application of lanthanide-doped nanocrystalline phosphors as biological labels would however strongly limit the photon turnover rates due to the long (ms to ms) decay time of their intraconfigurational 4f n luminescence.…”