Synthesis and spectroscopic investigations on Pr3+-doped LiPbB5O9 phosphor: A blue converting red phosphor for white LEDs

• Published in: Optik (Stuttgart) 2021-01, Vol.225, p.165758, Article 165758
• Main Authors: Raghu Raman, T., Ratnakaram, Y.C., Deva Prasad Raju, B.
• Format: Article
• Language: English
• Subjects: Concentration quenching; Diffuse-reflectance spectra; Lead oxide; Red emission; Solid-state reaction
• ISSN: 0030-4026; 1618-1336
• DOI: 10.1016/j.ijleo.2020.165758

•LiPbB5O9:Pr3+ phosphor is prepared by solid state reaction method.•The energy gap of LiPbB5O9:Pr3+ phosphors are in between 3.84–4.07 eV.•In LiPbB5O9:Pr3+ phosphor, energy transfer takes place due to dipole-dipole interaction.•The CIE colour co-ordinates of LiPbB5O9:Pr3+ phosphors show the red colour region.•LiPbB5O9:xPr3+ phosphors may find application as red light emitting phosphor for W-LEDs. In this study, various concentrations of Pr3+ doped LiPbB5O9 phosphors were synthesized via solid state reaction technique. For the prepared phosphors, X- ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric study (TG-DSC), diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) characterizations were performed. Crystallinity nature of LiPbB5O9:Pr3+ phosphor was studied by XRD analysis. Morphology of the prepared phosphors was investigated by SEM studies. Various functional groups present in LiPbB5O9:Pr3+ phosphor were identified through FTIR analysis. Variation in weight of the prepared phosphor with the temperature (endo- and exothermic temperatures) was studied by TG-DSC studies. Optical energy band gaps for different concentrations of Pr3+were obtained from DRS studies. Photoluminescence (excitation and emission) spectra were investigated at λemi = 609 nm and λexc = 443 nm, respectively. From energy transfer studies, it was identified that the energy transfer between Pr3+ ions in LiPbB5O9 phosphor was ascribed to dipole-dipole interaction. Lifetime decay curves of 1D2 level were studied at λemi = 609 nm and λexc = 443 nm wavelengths. CIE colour coordinates of LiPbB5O9:Pr3+ phosphors were calculated from the emission data. From all these studies, it can be mentioned that LiPbB5O9:0.05Pr3+ phosphor may be utilized for the blue light converting red phosphor in white LED applications.