Speaker
Mr
Machaba Leanyatsa Abraham Letswalo
(University of Johannesburg)
Description
A solid state method was used to prepare CaMoO4, CaMoO4:Eu3+, CaMoO4-BO,3:Eu3+,CaMoO4-PO4:Eu3+ and CaMoO4-SO4:Eu3+ powder phosphors. X-ray Powder diffraction (XRD), UV-Vis absorption spectroscopy, scanning electron microscopy (SEM) and photoluminescence (PL) spectroscopy were used to characterize the powders. The XRD results indicate that the substitution of anions (BO32-,PO42-and SO42-) and Eu3+ dopant ion did not affect the crystal structure of the CaMoO4 phosphors, but greatly influenced the PL intensities of the CaMoO4:Eu3+ phosphors. The luminescence spectra, excited at 395 nm using a monochromatized xenon lamp, for the four different CaMoO4:Eu3+ phosphors were recorded. The PL spectra showed an intense red emission at 615 nm belonging to the 5 D0 -> 7 F2 electric dipole transition. The highest PL intensity was observed from CaMoO4-SO4:Eu3+ sample. The decay curves were recorded when monitoring the 615 nm emission. All the decay curves were single exponential and lifetimes remain constant with a value in region of 430 microsecond (µs). The calculated CIE (Commission Internationale de l’Eclairage) confirmed that the emission color was lying in the red region. The PL data suggest that our materials have potential application as source of red light in red light emitting diode.
Main supervisor (name and email)<br>and his / her institution
Prof O.M Ntwaeaborwa
University of Wits
ntwaeab@gmail.com
Level for award<br> (Hons, MSc, <br> PhD, N/A)?
MSc
Apply to be<br> considered for a student <br> award (Yes / No)?
Yes
Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)?
yes
Primary authors
Mr
Machaba Leanyatsa Abraham Letswalo
(University of Johannesburg)
Prof.
Odireleng Martin Ntwaeaborwa
(University of Witwatersrand)
Co-authors
Dr
Balakrishna Avula
(University of The Free State)
Prof.
Hendrik Swart
(University of the Free State)
Dr
Leelakrishna Reddy
(University of Johannesburg)
