Luminescent characteristics of Eu3+ doped di-calcium silicate nano-powders for white LEDs

• Published in: Journal of alloys and compounds 2013-10, Vol.575, p.434-443
• Main Authors: Sunitha, D.V., Nagabhushana, H., Sharma, S.C., Nagabhushana, B.M., Chakradhar, R.P.S.
• Format: Article
• Language: English
• Subjects: Combustion; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Fourier transforms; Growth from solutions; Leda; Linearity; Luminescent centers; Materials science; Materials synthesis; materials processing; Methods of crystal growth; physics of crystal growth; Nanocrystalline materials; Nanophosphors; Nanopowders; Nanoscale materials and structures: fabrication and characterization; Nanostructure; Phosphors; Photoluminescence; Physics; Scanning electron microscopy; Thermoluminescence; White light; WLEDs
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2013.05.132

[Display omitted] •The β-Ca2SiO4:Eu3+ (1–5mol%) phosphors prepared using low temperature combustion method.•XRD, SEM and FTIR techniques used to characterize the phosphor.•TL and PL properties were well studied.•Prepared phosphor may be used for making the white LEDs and dosimetric applications.•The color purity has been verified by using the chromaticity diagram. Nanocrystalline Ca2SiO4:Eu3+ (1–5mol%) phosphors have been prepared by solution combustion process using DFH as a fuel which is less temperature compared to solid state route. The powders were well characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and Fourier Transform Infra-Red (FTIR) spectroscopy. PXRD results confirm the β-Ca2SiO4 phase upon calcination at 950°C for 3h. SEM micrographs indicate that the product is highly porous and agglomerated particles. Thermoluminescence (TL) studies have been carried out with γ-irradiation in the dose range 1–6kGy. Two TL glow peaks are recorded at ∼439 and ∼536K for all the Eu3+ concentrations (1–5mol%), the highest TL glow peak intensity was recorded for 4mol% Eu3+. The 439K glow peak increases linearly with γ-dose whereas, 536K glow peak follows sublinear. The kinetic parameters (E, b, s) have been estimated from different methods. Further, 439K TL glow peak show good linearity, hence it is quite useful in radiation dosimetry. The PL spectra consists of series of peaks at 565–580, 590, 613–618, 652–681nm respectively upon excited at different excitation wavelengths. These peaks are attributed to the transitions 5D0→7F0, 5D0→7F1, 5D0→7F2, 5D0→7F2, 5D0→7F3 and 5D0→7F4 respectively. The chromaticity co-ordinates of the Eu3+ activated samples are located in white light and hence the phosphor is highly useful for white LED’s.