Energy transfer in oxidic phosphors

Synthesis of Y3Al5O12:Eu and Y3Al5O12:Eu,Si phosphors by combustion method: Comparative investigations on the structural and spectral properties

“…To determine the dominant mechanism, the asymmetry ratio reveals information in the bonding nature between Eu 3+ ion and the surrounding anions. The asymmetric ratio was calculated by the ratio of the intensity of the electric dipole transition 5 Figure 11 illustrates the color perception related to luminescence of selective YAG:Eu and YAG:Eu,Si samples. Color perception can be stated in terms of the CIE coordinates given by the International Commission for Illumination mathematically.…”

“…And all entries have their usual meaning (e is the charge of electron,  is the energy of transition, h is Plank's constant, n is the refractive index, and J = 0 for the 5 …”

“…The concentration quenching will not occur beyond the critical distance. For this reason, it is possible to obtain the critical distance (R c ), which is the shortest distance between the nearest activator ions and can be calculated from the following formula [5]:…”

“…When Y 3+ ions in YAG doped with trivalent rare earth ions, such as Gd, Eu, Pr, Ce, and Tb, it can be widely used in optoelectronic devices [2][3][4]. At present, commercial white LED is mainly manufactured by combining a GaN based blue LED chip with Y 3 Al 5 O 12 :Ce 3+  (YAG:Ce) yellow phosphor [5]. But the LED faces problems of color separation between blue and yellow and poor color rendering caused by the lack of a red component in the spectrum.…”

Новый люминофор ИК-диапазона на основе германата Sr-=SUB=-3-=/SUB=-La-=SUB=-2-=/SUB=-(Ge-=SUB=-3-=/SUB=-O-=SUB=-9-=/SUB=-)-=SUB=-2-=/SUB=- : Nd-=SUP=-3+-=/SUP=-, Ho-=SUP=-3+-=/SUP=-

“…Наиболее близким по энергии к энергии возбуждения является метастабиль-ный уровень 4 F 3/2 Nd 3+ , с которого возможна передача части энергии гольмию по резонансно-индуктивному (мультипольному) механизму и переходу его из основ-ного состояния 5 [36], благоприятствует этому процессу: [40], которая сти-мулирует переход 2 F 7/2 → 2 F 5/2 с E ∼ 2200−2400 cm −1 (∼ 3hω ′ ), сопровождающийся испусканием трех фононов. Рассмотренные выше примеры указывают на генерацию фононов при диссипации возбужденного состояния ак-цептора.…”