Precisely adjusting the color purity of LaAlO 3 :Eu 3+ red phosphor with 593 and 618 nm emissions is achieved in a strategy of suppressing transitions of high energy levels of Eu 3+ ions through varying the doping concentration. As the doping concentration increases, the transitions from high levels 5 D 3,2,1 will be weakened, while those from 5 D 0 are enhanced up to a critical value with the aid of the cross relaxation. As a result, an increase of the color purity from 95.2% to 97.4% is obtained. It indicates that the red phosphor could be one of the excellent red-light-emitting phosphors in illuminating and display devices.For the applications of energy-saving fluorescent lamps, solid state lighting and high resolution display devices, phosphor materials [1][2][3] , especially red-light-emitting phosphors with a high color rendering index (CRI), high efficiency and high color purity are in the urgent need. Lots of candidate phosphors with those merits, including Eu 3+ -doped Na 5 La (MoO 4 ) 4 [4] , Gd 2 (MoO 4 ) 3 [5] , Y 2 O 3 [6] , CaO [7] , Gd 1-x Zn x O 3 [8] , Eu 2+ -doped Ca 1-x Sr x S [9] , Sr 2 Si 5 N 8 [10] , CaAlSiN 3 [11], Mn-doped BaZnOS [12] , CaAl 12 O 19[13] and Ce 3+ -doped CaSiN 2 [14] red phosphors, have emerged recently. Generally, due to the narrow line emission of Eu 3+ other than the broad band emission, Eu 3+ -doped red-light-emitting phosphors show better color purity than those with Eu 2+ and Ce 3+ . Specifically, there are two types of transitions for Eu 3+ : one is the electric dipole 5 D 0 -7 F 2 transition ranging from 610 to 625 nm as Eu 3+ occupies some sites of cations in a non-centrosymmetric lattice, and the other is the magnetic dipole 5 D 0 -7 F 1 transition, ranging from 590 to 600 nm as Eu 3+ substitutes some sites of cations in a centrosymmetric lattice [15] . Consequently, a dependence of the red-light-emission position on the CRI and lumen output could be established [16] . Namely, the emissions peaked in 610-625 nm exhibit higher CRI, while those peaked in 590-600 nm give greater lumen output than in other wavelength ranges.Thus, a compromise strategy is expected to explore a redlight-emitting phosphor with emissions covering both two ranges concurrently. In our previous results [17] , a perovskite type LaAlO 3 :Eu 3+ red phosphor is obtained with peaks at 593 nm and 618 nm, much similar to those reported by Ekambaram [16] and Hreniak [18] . However, some transition emissions from high levels ( 5 D 1,2,3 ) to 7 F J are still found in the blue-green region. These transitions are generally undesirable as they most likely degrade the color purity. Some efforts, therefore, have to be made to achieve higher color purity through suppressing transitions of Eu 3+ from high levels 5 D 1,2,3 to 7 F J , ensuring an efficient transition from 5 D 0 to 7 F 1 and 7 F 2 simultaneously.In this paper, we report an efficient adjustment for the color purity with the aid of the cross relaxation by simply varying the doping concentration of Eu 3+ ions.A conventional solid-state reaction me...
The influence of the polarized state of blue light on light scattering in InGaN blue chip nano-crystal luminescent glass for solid state lighting is investigated. Based on Rayleigh-Debye approximation theory, theoretical relationships between the light scattering turbidity and wavelength of the incident light, radius and refractive index of the nano-crystals are established to simulate the situations in yttrium aluminate garnet (YAG), silicate and oxynitride based luminescence glass. It is revealed that the scattering turbidity in luminescent glass turns to be the smallest as the effective refractive index of nanocrystals is equal to that of parent glass, and the scattering turbidity for the vertically polarized incident light is greater than that for the un-polarized incident light, while that for the horizontally polarized incident light is smaller than that for the unpolarized incident light under the same conditions. The present combination of InGaN/YAG: Ce 3+ type phosphorconverted white-light generally adopts a pattern with epoxy resin or silicone encapsulation, easily leading to unmatched refractive index between inhomogeneous materials, a lower efficiency of light extraction, degradation of materials and shift of light color as well. To solve these problems, photonic crystals [1][2][3] , transparency glass ceramics and nano-crystal luminescent glass [4,5] are considered to be candidates. We have proposed a technical route by using nanocrystalized luminescent glass as light guide materials, in which both luminescence and transparence have to be taken into account.Many approaches for light scattering in glass ceramics have been extensively done [6][7][8][9][10][11] and halide based systems were often concerned [6,11,12] . Specifically, Hendy [13] found k 8 R 7 dependence of the scattering turbidity, where k and R are the wave-number and the average crystal radius respectively. Edgar [14,15] proposed a light scattering model in glass ceramics based on the core-shell particle model and Rayleigh-Debye approximation, revealing a series of abnormal phenomena involved in this kind of glass ceramics.However, only the non-polarized incident light has been considered in all these approaches. Indeed, the polarized light emitted from the InGaN/GaN light emitting diodes (LEDs) has been proposed and experimentally confirmed by Schubert group [16] , which is of importance in many applications such as sensing, imaging and liquid crystal backlighting [17] . In this paper, taking into account of the incident polarization light, we employ Rayleigh-Debye formula to obtain the scattering turbidity with wavelength of incident light, radii and refractive index of nano-crystals. We assume that the nanometer phosphor particles are embedded in parent glass uniformly in spherical core-shell structure [14,15] , which has been precipitated by nucleation and grain growth with melt cooling-heat-treating procedure. Upon nucleation, the crystallite atoms and the primitive atoms are located in the grown crystal and then mutually diffuse wi...
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