Abstract
The ytterbium ions doped MO-Al 2O 3 (M=Ca, Sr and Ba) phosphors have been synthesized through combustion technique and their up and down conversion fluorescence properties have been studied and compared. The samples were calcinated at different temperatures and their FTIR and XRD spectra have shown a close relationship. With 976 nm excitation all these phosphors show cooperative upconversion emission at 488 nm from the pairs of two Yb 3+ ions along with an unexpected broad upconversion band in the blue green region and has been assigned to arise from the defect centers. Contrary to this upconversion emission, calcium aluminate phosphor exhibits bright and very broad down-conversion fluorescence (FWHM≈160 nm) upon UV (266 nm) excitation due to Yb 2+ ions. The inter-conversion between the 3+ and 2+ valence states of Yb ion has been observed on calcinations of samples in open atmosphere and has been correlated to the emission properties. The Yb 2+ ions containing calcium aluminate phosphor has been found suitable for producing broad band light in the visible region (white light). Lifetime of the emitting states of Yb 3+ and Yb 2+ ions have also been measured and discussed.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
