Efficient phosphors for mercury-free fluorescent lamps

[I]研究了将Xe准分子获得的172 nm波长的真空紫外光转换为可见光的高效荧光粉。2001年，我们研究了稳定氧化物，特别是稀土正磷酸盐中量子切割过程的可行性。结果表明，高能激发态稀土离子的非辐射弛豫和紫外区稀土离子之间的能量转移可以降低量子截断几率。而Pr~(3+)或Tm~(3+)向Gd~(3+)的能量传递导致了Gd~(3+)在312 nm处的有效发光线，可应用于灯的光催化活性。这种现象是由Pr3+或Tm3+的简单电子组态引起的，它们有两个4f电子或空穴。[II]2002年，我们研究了从主体到激活剂离子的能量转移激发的材料。(1)在172 nm的光激发下，用Gd取代YAlO_3：Eu~(3+)中的Y可以提高30%的效率。这个显著的效果结果是…更多的S来自于宿主晶体的吸收边通过Gd取代而红移。(2)在高效红色荧光粉中，SrTiO_3：Pr3+，Al从束缚激子向Pr3+提供能量。这项工作表明，基质的基频吸收带与Pr3+的4f-5d吸收带之间的能量重叠与发光效率有关。这种发射出现在阈值电子束电流之上，并且随着电子束电流密度的增加，强度急剧增加。到目前为止，在束流直径约0.3 mm的25KV电子激发下，获得的最低阈值为0.02 mA。如果阈值能够进一步降低，这种发射可能成为新的无汞光源的候选。较少

[I]Efficient phosphors were surveyed to convert VUV light of 172nm wavelength obtained from Xe excimers to visible light. In 2001, we investigated feasibility of quantum cutting processes in stable oxides, specifically rare-earth orthophosphates. The results showed that nonradiatative relaxation from a high-energy excited level of a rare-earth ion and energy transfer between rare-earth ions in the UV region can reduce the probability of the quantum cutting. However, energy transfer from Pr3+ or Tm3+ to Gd3+ leads to efficient Gd3+ luminescence line at 312nm, which can be applied to lamps, which activate photoactive catalysis. This phenomena result from simple electronic configurations of Pr3+ or Tm3+, which have two 4f electrons or holes.[II]In 2002, we investigated materials excited by energy transfer from a host to an activator ion.(1)Substitution of Y by Gd in red-emitting YAIO3:Eu3+ gives rise to 30% increase in efficiency under 172nm light excitation. This remarkable effect result … More s from a red shift of the absorption edge of the host crystal by Gd substitution. We also developed a synthesis method to provide a single-phase material of high efficiency, which uses theta alumina as a starting material and firing temperature as high as 15000.(2)In efficient red phosphor, SrTiO3:Pr3+, Al, energy is provided from the bound exciton to Pr3+.This work has shown that energy overlap between the fundamental absorption band of the host and 4f-5d absorption band of Pr3+ is correlated with the luminescence efficiency.[III]Bright warm-white emission was discovered by cathode-ray excitation of rugged powder layers of insulater materials. This emission appears above the threshold electron-beam current and drastically increases in intensity with an increase in the beam-current density. The lowest threshold so far obtained is 0.02mA under 25kV electron excitation with a beam diameter of about 0.3mm. This emission may be a candidate of new non-mercury light source if the threshold can be further decreased. Less