Effect of Ho3+ ion concentration on structure and spectroscopic properties of LiPbB5O9:Ho3+ phosphor

• Published in: Journal of molecular structure 2021-11, Vol.1243, p.130759, Article 130759
• Main Authors: Raman, T.R., Vijaya lakshmi, R.P., Ratnakaram, Y.C.
• Format: Article
• Language: English
• Subjects: CIE 1931 diagram; Energy band gap; Ho3+ ion; LiPbB5O9 phosphor; Photoluminescence; Solid-state reaction
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2021.130759

•LiPbB5O9:Ho3+ phosphor is prepared by solid state reaction method.•Energy transfer in LiPbB5O9:Ho3+ is attributed to “nearest neighboring ions”.•Color coordinates of LiPbB5O9:Ho3+ phosphors represent greenish-yellow region.•LiPbB5O9:0.08 Ho3+phosphor may find application in W-LEDs. Lithium lead borate (LiPbB5O9:Ho3+) phosphors doped with distinct concentrations of Ho3+ ions were prepared by solid state reaction technique. Structural characteristics were studied from X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and FT-Raman characterizations. Spectroscopic properties were studied from UV–Vis–NIR and photoluminescence (PL) spectra. From XRD investigations, crystallite sizes were calculated from Debye-Scherrer (D-S) and William-Hall (W-H) methods. Optical energy band gaps were calculated by using Tauc's relation for direct and indirect allowed transitions. The emission spectra of LiPbB5O9:Ho3+ phosphors were recorded by monitoring the excitation wavelength at λexc = 397 nm. Lifetime decay curves of 5S2 energy level of Ho3+ ion were studied for distinct concentrations of Ho3+ ions. Energy transfer mechanism was investigated for LiPbB5O9:Ho3+ phosphor. Concentration quenching was observed at 0.08 mol% of Ho3+ concentration among various concentrations. CIE color coordinates were computed and they showed the greenish-yellow region for various Ho3+ concentrations. The present, LiPbB5O9:0.08Ho3+ phosphor may be useful for the greenish-yellow emitting phosphor applications. [Display omitted]