Luminescence Mechanism and Thermal Stabilities of a White Silicate Phosphor for Multifunctional Applications

Abstract

A series of Dy3+‐doped Sr2(1−y)Ca2yY8(SiO4)6O2 (0 ≤ y ≤ 1) white phosphors were synthesized by the solid‐state reaction. All samples crystallize into a hexagonal crystal system with space group P63/m (176) by the determination of XRD Rietveld refinements. With the change in Ca/Sr ratio, the crystal environment of active ions is lightly affected. Upon excitation by UV/VUV/cathode ray sources, the samples present an efficient white light emission with significant differences in the blue/yellow ratio of Dy3+ characteristic transitions. Based on luminescence properties, decay times and thermal properties, the interesting phenomenon with excitation energy increasing from UV to electron beam can be reasonably explained by a potential mechanism we proposed. With the introduction of Bi3+, the white emission intensity is rapidly enhanced and the optimal intensity reaches to 3.75 times compared with the single doped Dy3+ sample. To evaluate the applicability of this phosphor, we packaged two light‐emitting diode devices and measured the actual luminescence efficacies and CIE chromaticity coordinates. These results indicate that the silicate phosphors have the potential for multifunctional application in ultraviolet‐based light‐emitting diodes, mercury‐free lamps, and field‐emission displays.

An energy self-compensating phosphosilicate material applied to temperature sensors

“…It is apparent that the CL intensities of three peaks (339, 441 and 614 nm) slowly decrease with increasing bombing time, which may be due to the following four reasons: (1) accumulation of graphitic carbon on the surface of the samples during continuous electron bombardment, resulting in carbon contamination, (2) accumulation of surface charges, (3) thermal quenching effects caused by the increase of the surface temperature of the sample over the long period of electron beam bombardment, (4) ground-state depletion. [44][45][46][47] In our work, the sample CAPS:0.03Ce, 0.005Eu has good degradation properties. When bombarded by a persistent electron beam for 90 min, the CL intensities of Ce 3+ , Eu 2+ , and Eu 3+ decreased to 67.1%, 72.3% and 71.8% of the initial values, respectively.…”

Tunable emission color of Li2SrSiO4:Tb3+ due to cross‐relaxation process and optical thermometry investigation

“…Silicate compounds have been extensively studied as host material for phosphors when doped by lanthanide ions . Silicate‐based phosphors have advantages such as relatively broad range of excitation, excellent luminescent characteristics, good chemical stability, easy, and inexpensive preparation .…”

“…13,14 Silicate compounds have been extensively studied as host material for phosphors when doped by lanthanide ions. [15][16][17] Silicate-based phosphors have advantages such as relatively broad range of excitation, excellent luminescent characteristics, good chemical stability, easy, and inexpensive preparation. 18,19 Particularly, Li 2 SrSiO 4 silicate have been investigated due to their diversiform crystal structures, excellent chemical, and thermal stability, in which rareearth ions are generally served as activator because of their abundant emission colors from 4f-4f or 5d-4f transitions.…”