| Autor: |
Duragkar A; Department of Chemistry, Sevadal Mahila Mahavidhyalaya, Nagpur, India., Dhoble NS; Department of Chemistry, Sevadal Mahila Mahavidhyalaya, Nagpur, India., Kohale RL; Department of Physics, Sant Gadge Maharaj Mahavidyalaya, Hingna, Nagpur, India., Dhoble SJ; Department of Physics, R.T.M. Nagpur University, Nagpur, India. |
| Abstrakt: |
In present work, KNa(SO 4 ) phosphors doped with different concentrations of rare earth Eu 3+ , Sm 3+ and Dy 3+ ions (0.05, 0.1, 0.3, 0.5, 0.7, 1 mol%) were synthesized using a solid-state diffusion technique. Photoluminescence (PL) investigations were carried out for the whole range of Eu 3+ , Sm 3+ and Dy 3+ -doped phosphors; rare earth ions that retained maximum PL intensity were selected for advanced anionic exchange. In the present investigation, phosphors KNa(SO 4 ):Eu 3+ (1 mol%), KNa(SO 4 ):Dy 3 + (0.5 mol%) and KNa(SO 4 ):Sm 3+ (0.3 mol%) had the highest PL intensity, and were therefore selected for further anionic substitution of sulphate anions with different concentrations of vanadate, phosphate, and tungstate anions, such as KNa(SO 4 ) 1-x (MO 4 ) x : W (where W = Eu 3+ 1 mol%, Dy 3+ 0.5 mol% and Sm 3+ 0.3 mol%; MO 4 = PO 4 , VO 4 , WO 4 ; and x = 0.1, 0.3, 0.5, 0.7, 1). Structural and molecular environments of the substituted phosphors were characterized individually using X-ray diffraction and Fourier transform infrared spectroscopy. In-depth morphological investigations of the prepared phosphors were undertaken using scanning electron microscopy. For the principal investigation on enhancement of white light-emitting diode (w-LED) performance, the PL properties of all the synthesized phosphors were studied analytically. Emission intensity ratios for KNa(SO 4 ):Eu 3+ 1 mol%, KNa(SO 4 ) 0 (PO 4 ) 1 :Eu 1 mol%, KNa(SO 4 ) 0.9 (VO 4 ) 1 :Eu 1 mol%, and KNa(SO 4 ) 0.9 (WO 4 ) 0.1 :Eu 1 mol% were 1:1.15:1.23:0.08. PL intensity ratios for the phosphors KNaSO 4 :Dy 0.5 mol% and KNa(SO 4 ) 0.9 (PO 4 )0.1:Dy 0.5 mol% was 1:2. The ratio of PL intensity was 1:3.2:0.8 for KNa(SO 4 ):Sm 1 mol%, KNa(SO 4 ) 0.5 (PO4) 0.5 :Sm 0.3 mol%, and KNa(SO 4 ) 0.7 (VO 4 ) 0.3 :Sm 0.3 mol% phosphors, respectively. Chromaticity investigations were carried out using Commission Internationale de l'Éclairage colour co-ordinate diagrams, which suggested that the prepared Eu 3+ -doped and Sm 3+ -doped phosphors would be prospective candidates for red and green LEDs, respectively, whereas Dy 3+ -doped phosphors showed emission in the blue and yellow regions. The entire study indicated that amalgamation of anionic exchange at a KNaSO 4 phosphor activated with Eu 3+ , Dy 3+ and Sm 3+ rare earth ions could generate and enhance white light emission.
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