2SrO · 3Al2 O 3 : Eu2 +  and 1.29 ( Ba , Ca )  O  , 6Al2 O 3 : Eu2 +  : Two New Blue‐Emitting Phosphors

Abstract

In the system SrO-A1203 a new compound was discovered with composition 2SrO -3A1203 (SAL); its structure is related to the one of 4SrO 9 7A1203 (SAE). The aluminate 1.29(Ba,Ca)O,6A1203 (BAL) belongs to the B-alumina type compounds and is closely related to BaMgA]10017 (BAM). The compounds SAL and BAL are good host lattices for highly efficient Eu 2 § luminescence. The europium emission peaks at 460 nm in SAL and at 440 nm in BAL. Both phosphors show a high output and good maintenance in low pressure Hg discharge lamps and are ideally suited for use in tricolor lamps.

Synthesis of lamp phosphors: facile combustion approach

“…Because of refractory nature of alumina and rare-earth oxides, conventional synthesis of lamp phosphors requires temperature greater than 1000 • C. Thus, corresponding metal oxides/carbonates are ground well and heated >1000 • C. The mechanism of solid state reactions is diffuse control reaction and hence, repeated grinding and repeated heating are required [36][37][38][39][40][41][42][43][44]. The controlled atmosphere is necessary to master the valence of the activator (for example Eu 2+ or Eu 3+ ) and the stoichiometry of the host lattice.…”

“…Quantity of BaAl 2 O 4 increases with increase of the barium content in barium hexa aluminate. According to Kimura and coworkers [67], coexistence of two phases (barium poor and barium rich) was indicated by the splitting in (1 0 7) reflections, whereas according to Smets et al [68] splittings of (0 0 1) reflections are more diagnostic indicators of the phase multiplicity. Therefore, selected reflections were recorded under slow scanning mode for high resolution.…”

Eu2+ activated long persistent strontium aluminate nano scaled phosphor prepared by precipitation method

“…However, it can only maintain phosphorescence no more than a few hours and its chemical stability is not satisfying. Therefore, it has been substituted by the strontium aluminates presently, SrAl 2 O 4 [1], for example, since they have excellent properties, such as high quantum efficiency [2], long persistence of phosphorescence and good stability [3,4].…”

Effect of composition on the luminescent properties of Sr4Al14O25: Eu2+, Dy3+ phosphors

“…However, conventional phosphorescent materials such as ZnS: Cu can hardly have bright light and long afterglow time for the applications. In recent years, the strontium aluminates hosts, for example SrAl 2 O 4 : Eu 2+ , Dy 3+ and Sr 4 Al 14 O 25 : Eu 2+ , Dy 3+ have attracted the researches intensely [1], since they have excellent properties such as high quantum efficiency [2], long persistence of phosphorescence and good stability [3,4].…”