Synthesis and Luminescence Characterization of LaBO3:Dy3+ Phosphor for Stress Sensing Application

Abstract

LaBO:xDy (x = 0.05 mol%, 0.1 mol%, 0.2 mol%, 0.5 mol%, 1 mol% and 2 mol%) phosphors were synthesized by solid-state reaction method. X-ray diffraction technique was used to confirm the formation of compound. Photoluminescence emission spectra shows two emission peaks at 470 nm and 575 nm when excitation wavelength is set at 352 nm. Photoluminescence intensity increases upto 1 mol % of Dy and then starts decreasing. Dipole-dipole interaction is found to be responsible for concentration quenching of photoluminescence intensity. Commission Internationale de I'Eclairage (CIE) chromaticity diagram demonstrates that the phosphor emits in bluish white region of the visible spectrum. Critical energy transfer distance between dopant ions was determined. The mechanoluminescence characteristics were studied by the impact method. The peaks of both the mechanoluminescence (ML) intensity and the total ML intensity of the UV exposed phosphors increases with increasing impact velocity for 1 mol % concentration of Dy. The ML sensitivity of the LaBO:Dy (Dy = 1 mol %) phosphor is comparable with the reported ML of various inorganic phosphors. The thermoluminescence characteristics of the samples were also investigated. Thermoluminescence glow peaks were recorded with 480 Gy, 80 Gy and 20 Gy dose of γ-irradiation from Co Source. TL trapping parameters were determined by Chen's peak shape method and glow curve deconvolution method. LaBO:Dy phosphors were found to be good mechanoluminescent materials and can be used in stress sensing application.

Структурные и спектральные характеристики ортоборатов Pr-=SUB=-1-x-=/SUB=-Lu-=SUB=-x-=/SUB=-BO-=SUB=-3-=/SUB=-

“…При дальнейшем увеличении концентрации Lu 3+ (при 0.8 < x < 0.95) количество мелких микрокристаллов (0.5−1 µm) уменьшается, а более крупных (∼ 2−4 µm) -увеличивается (рис. [23,24]. Соединения Pr 0.99−x Lu x Eu 0.01 BO 3 (0.95 ≤ x ≤ 0.99), имеющие структуру кальцита, состоят из микрокристаллов, размеры которых при x = 0.95 и 0.99 равны ∼ 2−4 и ∼ 3−10 µm соответственно (рис.…”

“…P2 1 /m), в которую LaBO 3 переходит при температуре 1488 • С [6,17]. Ионы La 3+ в структуре арагонита окружены девятью ионами кислорода, а ионы бора имеют тригональную координацию по кислороду [18][19][20][21][22][23][24][25]. Следует отметить, что в структуре кальцита, например в LuBO 3 , ионы Lu 3+ окружены шестью ионами кислорода, а атомы бора имеют такую же, как в арагоните, тригональную координацию по кислороду -(BO 3 ) 3− [26].…”

Color Tuning from Greenish-Yellow to Orange-Red in Thermal-Stable KBaY(MoO4)3:Dy3+, Eu3+ Phosphors via Energy Transfer for UV W-LEDs

“…Generally, the yellow emission is dominant when Dy 3+ occupies a low-symmetry site, while the blue one governs the emission spectrum when Dy 3+ locates at a higher-symmetry site . To date, a large amount of Dy 3+ -doped phosphors has been reported to emit white light by combining two main characteristic emissions of the blue and yellow bands in LaBO 3 :Dy 3+ , BaGd 2 ZnO 5 :Dy 3+ , Sr 3 Y­(PO 4 ) 3 :Dy 3+ , (Y, Gd)­PO 4 :Dy 3+ , Ba 3 Bi 2 (PO 4 ) 4 :Dy 3+ , Li 4 CaB 2 O 6 :Dy 3+ , LaGdSiO 5 :Dy 3+ and so forth. − However, the lacking red component makes them unsatisfied for further applications. Recently, Eu 3+ was demonstrated to compensate the red component in various Dy 3+ , Eu 3+ codoped phosphors mainly attributed to its 5 D 0 → 7 F 1 magnetic dipole transition and 5 D 0 → 7 F 2 electric dipole transition. − Therefore, it is of much interest to develop Dy 3+ , Eu 3+ codoped color-tunable phosphors that can be applied in UV w-LEDs based on the energy-transfer effect.…”

“…Therefore, searching for an appropriate host material for rare earth ion doping is a crucial point to obtain good luminescence properties. Recently, several kinds of host materials comprising molybdates, tungstate, germinate, vanadates, phosphates, ,, titanates, silicate, niobates, and borate ,, have been selected as candidates for rare earth ion doping, in which molybdates are extensively investigated on account of their high chemical and physical stability properties, effective charge transfer (CT) absorption band, low preparation temperature and so forth. In order to acquire a better interpretation on their excellent properties, a large amount of efforts has been devoted to rare earth ion-doped molybdate phosphors. − In 1990, a series of novel KBaRE­(MoO 4 ) 3 (RE = La–Lu, Y, and Sc) were the first reported compounds by Kozhevnikova et al Until 2015, the Nd 3+ -doped laser crystal KBaY­(MoO 4 ) 3 was synthesized via a single crystal growth method by Wang’s group, in which the structural details were analyzed, showing its monoclinic system with space group C 2/ c .…”

“…Therefore, searching for an appropriate host material for rare earth ion doping is a crucial point to obtain good luminescence properties. Recently, several kinds of host materials comprising molybdates, 31 tungstate, 15 germinate, 36 vanadates, 18 phos-phates, 23,27,28 titanates, 37 silicate, 31 niobates, 38 and borate 17,24,25 have been selected as candidates for rare earth ion doping, in which molybdates are extensively investigated on account of their high chemical and physical stability properties, effective charge transfer (CT) absorption band, low preparation temperature and so forth. In order to acquire a better interpretation on their excellent properties, a large amount of efforts has been devoted to rare earth ion-doped molybdate phosphors.…”