Synthesis and Characterization of Lightweight Beryllium Chloro Silicate Phosphor

In this chapter, low weight barium-based cholorsilicate Ba5Cl6Si2O6:Eu2+ is prepared through a solid-state reaction. To confirm the structure of the synthesized phosphors, powder photographs were obtained using an x-ray diffractometer. Photoluminescence spectra and FTIR spectra were recorded. Photoluminescence spectra are studied. The emission peak is observed at 407 nm at excitation 275 nm. The intense violet-blue emission is obtained. The broad excitation band and strong emission indicate that Ba5Cl6Si2O6:Eu2+could be a good phosphor candidate for blue LED and white LEDs. Decay curve indicates the phosphor has a long afterglow feature.

Effect of Li+ doping on the luminescence performance of a novel KAlSiO4:Tb3+ green-emitting phosphor

A new green-emitting phosphor, KAlSiO4:1.5 mol% Tb3+, x mol% Li+, was prepared via a high-temperature solid-phase method, and its crystal structure, diffuse reflectance spectrum, and luminescence were studied. The results show that the Li+ doping shifts the strongest diffraction peak to a high angle direction, reducing grain size by 11.4%. The entry of Li2CO3 improves the luminescence performance of KAlSiO4:1.5 mol% Tb3+. At a Li+ concentration of 1.5 mol%, the sample has strong absorption in the ultraviolet light range from 250 to 400 nm. The luminous intensity of the sample at 550 nm approximately quadruples after Li+ doping. Additionally, the colour purity of the sample and the internal quantum yield increase to 83.3% and 42%, respectively. The sample changes colour with time when exposed to air without an obvious fading phenomenon. The emission intensity at 200 °C is 95.1% of its value at room temperature, indicating that the phosphor has excellent thermal stability when x = 1.5. These results show the feasibility of using the silicate phosphor for generating the green light component of white light-emitting diodes for solid-state lighting.

SYNTHESIS, CHARACTERIZATION AND PHOTOLUMINESCENCE PROPERTIES OF EU3+DOPED CALCIUM SILICATE PHOSPHOR BY CONVENTIONAL SOLID STATE REACTION METHOD

Calcium Silicate phosphor acquires a higher luminous efficiency when it is doped with rare earth activated ions. Silicate phosphors are used for a fluorescent, a cathode-ray tube, a luminous body, a vacuum ultraviolet excitation light emitting element etc. The silicates of calcium are known for their thermal stability, high temperature strength, low thermal expansion, cheep residence and chemical inertness. The present paper reports on the synthesis, characterization and photoluminescence properties of Eu3+ doped calcium silicate phosphor prepared by conventional solid state reaction method heating at 12000C for 3 hrs. The received cakes are grounded for 30 minutes each. The phosphors are prepared and the received powder is subjected to PL, XRD, SEM, EDAX and CIE analysis. The following section discusses and the experimental results are mentioned in these phosphors. The present Phosphor can act as a host for red light emission in many display devices and technological applications.