Synthesis, characterization, and enhanced photoluminescence of ZrO2:Dy3+ phosphors by incorporating Li+, Na+ and K+ ions for LED applications

ZrO2: (0.01)Dy3+:xA+ (A = Li+, Na+ and K+) phosphors were prepared by one step solution combustion method. X-ray diffraction (XRD), reveal formation of different phases. Functional group presence and its vibrations are assigned from FTIR measurements. Influence of alkali metal ions (A+) on surface morphology were realized from SEM micrograph. XPS study was carried out to confirm the presence of Li+ ions. Photoluminescence (PL) spectra of the samples excited at 350 nm exhibited two strong emission peaks at 480 nm and 580 nm, which are characteristic transitions of Dy3+ ions. However, the relative intensity between these peaks varies considerably due to the variation of the co-dopant/compensator (Li, Na, K) concentration, representing the variation of the crystal field. Effects of different charge compensators (A+) and their concentration on the structural and luminescence properties of ZrO2: (0.01)Dy3+:xA+ phosphors were thoroughly investigated. Further, Judd-Ofelt parameters were calculated. Total emission colour (TEC) concentration of ZrO2: (0.01)Dy3+ phosphors were improved remarkably with the addition of charge compensators (A+), which would promote their applications in solid state lighting. The effective blue emission of the phosphors was changing with different co-dopant incorporation. Implying possible use of this material as a blue emitting phosphor as a blue emitting component in three-component white light-emitting diodes (WLEDs).