Eu2+ as the structural probe in the phase transformation of CMSA by site-selective occupancy and adjustable multimode white luminescence in Ca2(Mg0.5Al0.5)(Si1.5Al0.5O7) akermanite based on high-aluminum blast furnace slag

A tunable multimode white emission Ca₂(Mg_0.5Al_0.5)(Si_1.5Al_0.5O₇):Eu²⁺/Eu³⁺ phosphor was prepared by doping Eu₂O₃ in molten high-aluminum blast furnace slag. The structural probe Eu²⁺ was studied during phase transformation between the glassy state and Ca₂(Mg_0.5Al_0.5)(Si_1.5Al_0.5O₇) crystals based on site-selective Eu²⁺ occupancy. When the doped Eu²⁺ ions occupied two different Ca²⁺ sites in the matrix, blue light (421 nm) and green light (516 nm) emissions were observed corresponding to two types of Eu²⁺_Ca²⁺, namely Eu²⁺_Ca²⁺ (Mg²⁺ → Al³⁺) and Eu²⁺_Ca²⁺ (Si⁴⁺ → Al³⁺). The effects of Eu concentration (0.1-2.0 mol%), heat treatment temperature (800-1000 °C), and thermal quenching temperature (30-150 °C) on the structural evolution of the emission unit were studied by differential scanning calorimetry (DSC), photoluminescence spectroscopy (PL) and X-ray diffraction (XRD) analyses. The Eu²⁺_Ca²⁺ (Mg²⁺ → Al³⁺) structure formed by site-selective Eu²⁺ occupancy possessed better structural stability in the Ca₂(Mg_0.5Al_0.5)(Si_1.5Al_0.5O₇) crystal matrix, in favour of light-emitting diode (LED) illumination and plasma display panels (PDPs).

Cation–anion substitution induced spectral tuning and thermal stability optimization in Sr2SiO4:Eu phosphors

The cation–anion substitution results in spectral tuning and thermal stability optimization in Sr₂Si_1−xAl_xO_4−2xN_x:Eu phosphors.

Dopant distribution and influence of sonication temperature on the pure red light emission of mixed oxide phosphor for solid state lighting

In this study, europium doped yttrium gadolinium (Y1.4Gd0.5Eu0.1O3) mixed oxide phosphors were synthesized by a sonochemical method at different growth temperatures (50°C, 100°C, 150°C and 200°C) for pure red light emission applications. The compositional identification, presence of dopants and the distribution of doping materials in the crystal lattice was studied by TOF-SIMS. The formation and growth mechanisms in the sonochemical synthesis of Y1.4Gd0.5Eu0.1O3 nanophosphors are discussed in detail. Different spectral and Judd-Ofelt parameters were estimated from photoluminescence data. Optical gain and efficiency parameters were calculated with the variation of synthesis environment and an efficient synthesis method to make good red emitting phosphors for solid-state lighting and display applications were proposed.

Sr9Mg(1.5)(PO4)7:Eu(2+): A Novel Broadband Orange-Yellow-Emitting Phosphor for Blue Light-Excited Warm White LEDs

A new orange-yellow-emitting Sr9Mg(1.5)(PO4)7:Eu(2+) phosphor was prepared via high-temperature solid-state reaction. The structure and optical properties of it were studied systematically. Sr9Mg(1.5)(PO4)7:Eu(2+) can be well-excited by 460 nm blue InGaN chips and exhibit a wide emission band covering from 470 to 850 nm with two main peaks centered at 523 and 620 nm, respectively, which originate from 5d-4f dipole-allowed transitions of Eu(2+) in different crystallographic sites. The sites attribution, concentration quenching, fluorescence decay analysis, and temperature-dependent luminescence properties were investigated in detail. Furthermore, a warm white LED device was fabricated by combining a 460 nm blue InGaN chip with the optimized orange-yellow-emitting Sr9Mg(1.5)(PO4)7:Eu(2+). The color coordinate, correlated color temperature and color rendering index of the fabricated LED device were (0.393, 0.352), 3437 K, and 86.07, respectively. Sr9Mg(1.5)(PO4)7:Eu(2+) has great potential to serve as an attractive candidate in the application of blue light-excited warm white LEDs.

Unusual near-white electroluminescence of light emitting diodes based on saddle-shaped porphyrins

In contrast to the red electroluminescence emission frequently observed in porphyrins based OLED devices, the present devices exhibit a nearly white emission with greenish yellow, yellowish green and blue green hues in the case of Fe(II)(TCPPBr6) (TCPPBr6 = β-hexabromo-meso-tetrakis-(4-phenyl carboxyl) porphyrinato), Zn(II)(TPPBr6) and Co(II)(TPPBr6), respectively.

Facile synthesis and optical properties of Ce:YAG polycrystalline ceramics with different SiO2 content

According to the FESEM micrographs of the as-prepared samples, they show the texture of polycrystalline materials and better uniformity appears in sample A.

Synthesis, structure, and peculiar green emission of NaBaBO3:Ce3+ phosphors

Polycrystalline samples of Ce³⁺-doped NaBaBO₃ (0.5–15 mol%) were prepared by the solid-phase synthesis.