Preparation of Compensation Ions Codoped SrTiO₃:Pr³⁺ Red Phosphor with the Sol-Gel Method and Study of Its Luminescence Enhancement Mechanism

Table 1

Calculated Mulliken population analysis for SrTiO₃:Pr³⁺: SrTiO₃:Pr³⁺, Mg²⁺, and SrTiO₃:Pr³⁺, Al³⁺ samples.

Mulliken bond population
SrTiO3:Pr^3+			SrTiO3:Pr^3+, Mg^2+			SrTiO3:Pr^3+, Al^3+
Bond	Population	Length (nm)	Bond	Population	Length (nm)	Bond	Population	Length (nm)
Sr–O	−0.03	0.2760	Sr–O	−0.04	0.2765	Sr–O	−0.04	0.2764
Ti–O	0.62	0.1952	Ti–O	0.65	0.1933	Ti–O	0.68	0.1919
Pr–O	0.12	0.2700	Pr–O	0.15	0.2608	Pr–O	0.15	0.2609
—	—	—		0.66	0.1902		0.70	0.1893
—	—	—	Mg–O	−0.10	0.2015	Al–O	0.40	0.1910

and are the atoms that are near the impurity atoms (Al and Mg).