Light-Emitting Diodes. (Monographs in Electrical and Electronic Engineering.) By A. A. Bergh and P. J. Dean. Pp. viii+591. (Clarendon: Oxford; Oxford University: London, 1976.) £22.

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Light-emitting diodes

Utilizing energy transfer (ET) between the sensitizer and acceptor in phosphors is a good way to obtain tunable emission color. Therefore, many researchers have devoted their interest to design phosphors with different emission colors via their energy transfer properties. It is well known that Ce3+ and Bi3+ are good sensitizers, while Mn2+, Dy3+, Eu3+ and Sm3+ can be useful activators. Further, Eu2+ and Tb3+ can be both good sensitizers and activators. Therefore, herein we summarise many recent ET systems consisting of Eu2+–Mn2+/Tb3+, Eu2+–Tb3+–Mn2+/Eu3+/Sm3+, Ce3+–Mn2+/Tb3+/Dy3+/Eu2+, Ce3+–Tb3+–Mn2+/Eu3+/Sm3+, Bi3+–Eu3+/Sm3+ and Tb3+–Eu3+/Sm3+, which show tunable emission color from ultraviolet to blue and green, blue to green, yellow, orange and pink/red, cyan to green, orange and pink/red, and green to yellow/orange and red. Based on this summary, this review will be a good reference to benefit the design and investigation of phosphors potentially applied in FEDs and LEDs with ET.

Recent development in phosphors with different emitting colors via energy transfer

Single-phase cool white-light emitting BaNb2O6:Dy3+ phosphors have been synthesized via a conventional solid-state reaction method and characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) observations and spectrofluorophotometric measurements. XRD and Rietveld structural refinement studies confirm that all the samples exhibit pure orthorhombic structure [space group – C2221(20)]. SEM observations reveal the dense particle packaging with irregular morphology in a micron range. The as-prepared phosphors exhibit blue (482 nm) and yellow (574 nm) emissions under 349, 364, 386 and 399 nm excitations corresponding to 4F9/2 → 6HJ (J = 15/2, 13/2) transitions of Dy3+ ions. The energy transfer mechanism between Dy3+ ions has been studied in detail and the luminescence decay lifetime for the 4F9/2 level was found to be around 146.07 μs for the optimized phosphor composition. The calculated Commission Internationale de L'Eclairage (CIE) chromaticity coordinates for the optimized phosphor are (x = 0.322, y = 0.339), which are close to the National Television Standard Committee (NTSC) (x = 0.310, y = 0.316) coordinates. The values of CIE chromaticity coordinates and correlated color temperature (CCT) of 5907 K endorse cool white-light emission from the phosphor. The study reveals that BaNb2O6:Dy3+ phosphor could be a potential candidate for near ultra-violet (NUV) excited white-LED applications.

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Emerging cool white light emission from Dy3+ doped single phase alkaline earth niobate phosphors for indoor lighting applications

Rare earth (RE) doped phosphors and their emerging applications: A review

Spectroscopic investigation on thermally stable Dy3+ doped zinc phosphate glasses for white light emitting diodes

Red light emitting BaNb2O6:Eu3+ phosphor for solid state lighting applications

Synthesis and enhancement of photoluminescent properties in spherical shaped Sm3+/Eu3+ co-doped NaCaPO4 phosphor particles for w-LEDs

BaNb2O6:Eu3+ phosphors (1, 4, 10, 12, 14, 16 mol% Eu) are prepared by calcination of stoichiometric amounts of BaCO3, Nb2O5, and Eu2O3 in air (1.

B. Sivaiah

Papers

Emerging cool white light emission from Dy3+ doped single phase alkaline earth niobate phosphors for indoor lighting applications

Red light emitting BaNb2O6:Eu3+ phosphor for solid state lighting applications

Synthesis and enhancement of photoluminescent properties in spherical shaped Sm3+/Eu3+ co-doped NaCaPO4 phosphor particles for w-LEDs

Red Light Emitting BaNb2O6:Eu3+ Phosphor for Solid State Lighting Applications.