New physical insight into crystal structure, luminescence and optical properties of YPO4:Dy3+∖Eu3+∖Tb3+ single-phase white-light-emitting phosphors

Single phase multi color emitting Ca2LuTaO6: Dy3+/Eu3+ double perovskite oxide phosphors

“…Solid‐state lighting is the fourth generation of lighting source has recently received great attention to replacing the traditional incandescent and fluorescent lighting source. Considerable development has been made in the phosphors converted white light‐emitting diodes (white‐LEDs) due to their highly stable white light emission, long working life time, high tunable brightness, low power consumption, and eco‐friendly behavior, etc 1‐5 …”

“…The trivalent Dy 3+ and Eu 3+ activated phosphors demonstrate their characteristics narrow band line emission in the blue to the yellow and white spectral region for Dy 3+ and orange to red emission for Eu 3+ doped in different host lattice phosphors 24‐26 . More interestingly, due to the 4 f 9 electronic configuration, which exhibits two dominant emission bands in the desired wavelength range of white light generation, the trivalent Dy 3+ ions are regarded as effective activators.…”

“…More interestingly, due to the 4 f 9 electronic configuration, which exhibits two dominant emission bands in the desired wavelength range of white light generation, the trivalent Dy 3+ ions are regarded as effective activators. More precisely, the Dy 3+ activated phosphors display a double emission band in the blue spectral region (470–500 nm), due to the magnetic dipole transition and in the yellow spectral region (570–600 nm) as a result of the electric dipole transition ( 4 F 9/2 → 6 H 15/2 ) 24,25 …”

“…The photoluminescence intensity of both the emission bands depends on the surrounding environment of the phosphors host lattice around the activated Dy 3+ ions 24,27 . Therefore by choosing the proper host materials to generate high‐ quality white light, the luminescence intensities of both the emission bands of the doped Dy 3+ ions will adjust the blue to yellow emission ratio (blue/yellow = 1) 24,25 . However, due to the highly shielded 4f electronic shell, Dy 3+ displays 4f – 4f spin forbidden transition, which is usually not favorable for the generation of highly efficient luminescence 28‐30 …”

Warm-white luminescence of Dy3+ and Sm3+ co-doped NaSrPO4 phosphors through energy transfer between Dy3+ and Sm3+ ions

“…By adjusting the ratio of the Dy 3+ to Sm 3+ concentration, excellent white light emissions, especially warm white, can be achieved. Phosphates are extensively utilized as phosphor hosts for their low synthesis temperatures and good chemical and thermal stability, including Ca2Sr(PO4)2:Dy 3+ [29], LiCaPO4:Ce [30], and YPO4:Dy 3+ \Eu 3+ \Tb 3+ [31]. Wet chemical methods can provide low synthesis temperatures, good crystal structures, and excellent luminescence properties.…”