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To improve the longevity of a phosphor converted white light-emitting diode (LED), the SinormalO2 coating on CaS:Eu phosphor by using polymer binder was carried out. The coating characteristics were found to be critically dependent on the sort of monomer and temperature of the reaction during the polymerizing process. This process is found to avoid a hydrolysis reaction, which causes damage to CaS:Eu phosphor surface, which frequently occurs in the conventional sol-gel process. Field-emission scanning electron microscope images and transmission electron microscopy images showed that polymer binder coating of SinormalO2 on CaS:Eu phosphor was very solid and could well serve as a protective layer against the moisture, which is critically detrimental to the development of commercial white LEDs. Significant optical stability, even after a moisture-contacting experiment, was observed in the case of coated phosphors. However, it was also found that the emission of normalH2S from the CaS:Eu phosphor still remained influential to the longevity of an LED device because of a bottom Ag plate in our experimental regime.

A phosphor screen which operates at low excitation energy must show good emission efficiency and sustain stabilities against high vacuum and high current density operation. In this study, low voltage phosphors suitable for FED applications were experimentally addressed and screened onto ITO-glass by the electrophoretic deposition which offers several advantages, including easy control of film thickness and high packing density. Process variables such as deposition rate, salt concentration, etc., in electrophoretic deposition method were optimized to achieve high quality of the screens. Correlations of process variables with particle size, surface morphology and luminescent properties of phosphors will be presented. Particularly, much attention was put on the optimization of phosphor screens for the maximal CL intensities and adhesion of particles over substrate when excited by field emitter arrays.

The objective of this work is to find a green phosphor for plasma display panels which has both high luminescence and a short decay time. A new green phosphor, ͑Y 1−x−y Gd x ͒Al 3 ͑BO 3 ͒ 4 :Tb y 3+ ͑0.05 ഛ x ഛ 0.5, 0.1 ഛ y ഛ 0.5͒, was synthesized by a fluxassisted solid reaction and its vacuum UV excitation and emission characteristics were examined. We found that under 147 and 172 nm excitations, ͑Y 0.3 Gd 0.2 ͒Al 3 ͑BO 3 ͒ 4 :Tb 0.5 3+ phosphors showed a strong green emission at 535-555 nm corresponding to the electric dipole 5 D 4 → 7 F 5 transition of Tb 3+ . The luminance of ͑Y 0.3 Gd 0.2 ͒Al 3 ͑BO 3 ͒ 4 :Tb 0.5 3+ at the 147 nm excitation was higher than that of YBO 3 :Tb 3+ , while the spectrum and decay time of the Tb ion was about the same as that of the commercial phosphor ͑YBO 3 :Tb 3+ ͒.Recently, plasma display panels ͑PDP͒ have been regarded as the most promising candidate for large-size flat panel display applications. 1-4 However, PDPs face stiff competition from liquid crystal displays ͑LCDs͒, where production is rising rapidly in the 40-44 in. range. Furthermore, PDPs need to have improved luminous efficacy, lower cost, and higher image quality to compete with other flat display devices including LCDs and organic light-emitting diodes. This strong competition will naturally lead to technology breakthroughs and lower prices for the consumer.PDPs are emissive devices, similar to older technology such as cathode ray tubes. PDPs use visible rays from phosphors excited by vacuum UV ͑VUV͒ radiation of 147 and 172 nm, which are generated by discharging mixed gas in red ͑R͒, green ͑G͒, and blue ͑B͒ cells. The luminous efficiency of a PDP depends upon various factors including the materials used in its fabrication ͑i.e., phosphors, the gas mixture, the dielectric layer material, the reflective layer material͒ as well as the cell dimensions, size and shape of electrodes, the address waveforms, and the operating voltage. 5,6 R, G, and B phosphors are critical in that they determine the picture quality of the PDP. The green component is particularly important as perception in the human eye lies more toward green in the visible spectrum. Green phosphors also can improve the color point of white light and boost the overall brightness of the display device.Refractory oxide compounds with aluminate, silicate, or borate groups have strong absorption in the VUV region. 7-11 Particularly, Mn 2+ -activated Zn 2 SiO 4 phosphor is used in PDPs as a greenemitting component due to its availability and high quantum efficiency, but Zn 2 SiO 4 :Mn 2+ phosphor exhibits a wide spectrum of emission with low color purity, long persistence, and fast saturation with VUV flux. Tb-activated green-emitting borate and phosphate phosphors have been studied and are widely used in compact fluorescent lamps due to their quantum efficiency and stability at high temperatures. 12,13 Also, in a recent study, a borate-based Tbactivated green phosphor improved the uniformity of the discharge characteristics of PDPs. 14 Among borate phosphors...

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