Optoelectronic characterization of Eu³⁺ doped MLa₂O₄ (M = Sr, Ca, Mg) nanophosphors for display devices

Figures & data

Figure 1. A schematic presentation for the synthesis of Eu³⁺-activated MLa₂O₄ (M = Sr, Ca, Mg) nanophosphors.

Figure 2. Photoluminescence spectra of SrLa₂O₄:Eu³⁺ excited at 395 nm. (a) Temperature variation (b) Concentration variation.

Figure 3. Photoluminescence spectra of CaLa₂O₄:Eu³⁺ excited at 395 nm. (a) Temperature variation (b) Concentration variation.

Figure 4. Photoluminescence spectra of MgLa₂O₄:Eu³⁺ excited at 395 nm. (a) Temperature variation (b) Concentration variation.

Figure 5. Photoluminescence spectra of La₂O₃:Eu³⁺ and MLa₂O₄:Eu³⁺ (M = Sr, Ca, Mg) nanophosphor showing variation of metal ions in host lattice.

Table 1. Color co-ordinates of phosphors at varying concentrations and at varying calcination temperatures

Phosphor compounds	Color co-ordinates
	500°C	750°C	950°C
SrLa2O4:Eu^3+ (0.01)	x-0.5086	x-0.5178	x-0.5245
	y-0.2878	y-0.2838	y-0.2829
SrLa2O4:Eu^3+ (0.02)	x-0.5184	x-0.5250	x-0.5363
	y-0.2868	y-0.2824	y-0.2804
SrLa2O4:Eu^3+ (0.03)	x-0.5354	x-0.5463	x-0.5563
	y-0.2846	y-0.2831	y-0.2816
SrLa2O4:Eu^3+ (0.04)	x-0.5446	x-0.5856	x-0.5909
	y-0.2783	y-0.2734	y-0.2723
SrLa2O4:Eu^3+ (0.05)	x-0.5261	x-0.5310	x-0.5423
	y-0.2853	y-0.2843	y-0.2807
CaLa2O4:Eu^3+ (0.01)	x-0.5289	x-0.4335	x-0.4382
	y-0.2838	y-0.2765	y-0.2766
CaLa2O4:Eu^3+ (0.02)	x-0.5301	x-0.5376	x-0.5423
	y-0.2786	y-0.2698	y-0.2665
CaLa2O4:Eu^3+ (0.03)	x-0.5324	x-0.5423	x-0.5489
	y-0.2764	y-0.2709	y-0.2679
CaLa2O4:Eu^3+ (0.04)	x-0.5347	x-0.5434	x-0.5567
	y-0.2738	y-0.2643	y-0.2635
CaLa2O4:Eu^3+ (0.05)	x-0.5310	x-0.5406	x-0.5468
	y-0.2745	y-0.2712	y-0.2658
MgLa2O4:Eu^3+ (0.01)	x-0.5235	x-0.5307	x-0.5398
	y-0.2769	y-0.2669	y-0.2650
MgLa2O4:Eu^3+ (0.02)	x-0.5276	x-0.5328	x-0.5409
	y-0.2749	y-0.2726	y-0.2713
MgLa2O4:Eu^3+ (0.03)	x-0.5293	x-0.5346	x-0.5476
	y-0.2736	y-0.2702	y-0.2649
MgLa2O4:Eu^3+ (0.04)	x-0.5321	x-0.5387	x-0.5439
	y-0.2766	y-0.2734	y-0.2665
MgLa2O4:Eu^3+ (0.05)	x-0.5289	x-0.5327	x-0.5432
	y-0.2735	y-0.2716	y-0.2709

Figure 6. Chromaticity diagram of synthesized MLa₂O₄:Eu³⁺ (0.04 mol) nanophosphors calcined at 950°C. (a) MgLa₂O₄:Eu³⁺ (b) CaLa₂O₄:Eu³⁺ (d) SrLa₂O₄:Eu³⁺.

Figure 7. SEM micrograph of (a) SrLa₂O₄:Eu³⁺ (b) CaLa₂O₄:Eu³⁺ (c) MgLa₂O₄:Eu³⁺.

Figure 8. TEM micrograph of (a) SrLa₂O₄:Eu³⁺ (b) CaLa₂O₄:Eu³⁺ (c) MgLa₂O₄:Eu³⁺.

Figure 9. XRD patterns of synthesized SrLa₂O₄:Eu³⁺ phosphors.

Figure 10. XRD patterns of synthesized CaLa₂O₄:Eu³⁺ phosphors.

Figure 11. XRD patterns of synthesized MgLa₂O₄:Eu³⁺ phosphors.

Table 2. Detailed description of size and phase of particle of SrLa₂O₄:Eu³⁺

Nanophosphor	SrLa2O4:Eu^3+
Temperature	500°C	750°C	950°C
Phase	Major La2O3 + Minor La2SrOx	La2SrOx	La2SrOx
2θ value	18.32	30.06	30.06
FWHM (radian)	0.02067	0.01135	0.00697
Particle size (nm)	7.07	14.12	19.91

Table 3. Detailed description of size and phase of particle of CaLa₂O₄:Eu³⁺

Nanophosphor	CaLa2O4:Eu^3+
Temperature	500°C	750°C	950°C
Phase	Major La2O3 matches with JCPDS No. 005-0602	Nearly matched with XRD of SrLa2O4:Eu^3+ No further records are found up to now
2θ value	29.498	30.06	30.06
FWHM (radian)	0.016048	0.01186	0.00942
Particle size (nm)	9.927	13.0493	16.0228

Table 4. Detailed description of size and phase of particle of MgLa₂O₄:Eu³⁺

Nanophosphor	MgLa2O4:Eu^3+
Temperature	500°C	750°C	950°C
Phase	Major La2O3 matches with JCPDS No. 005-0602	No records are found up to now
2θ value	29.498	30.036	30.036
FWHM (radian)	0.019223	0.01238	0.009507
Particle size (nm)	8.296	12.938	16.848