节能灯用BaMgAl10O17:Eu2+,Mn2+荧光粉的劣化机理研究

对节能灯用BaMgAl₁₀O₁₇: Eu²⁺,Mn²⁺荧光粉的热劣化和紫外辐照劣化机理进行了对比研究. 发现热处理和紫外辐照处理均对BaMgAl₁₀O₁₇: Eu²⁺,Mn²⁺产生明显的发光劣化作用. 研究结果表明：热劣化主要涉及到Eu²⁺ 的氧化及其格位偏移, 而紫外辐照劣化与上述过程无关. 紫外辐照劣化主要源自高能紫外辐照使Eu²⁺ 处于更加不稳定的状态, 从而降低Eu²⁺ 的直接吸收和发射强度.     

助熔剂法制备的(Ce0.67,Tb0.33)MgAl11O19绿色荧光粉的发光性能

选取典型的助熔剂,利用助熔剂法制备了节能灯用(Ce0.67,Tb0.33)MgAl11O19绿色荧光粉,并对其发光性能进行了对比测试。研究了各单一或复合助熔剂对(Ce0.67,Tb0.33)MgAl11O19荧光粉的发光亮度及颗粒形貌的作用及影响,并找到了最佳复合助熔剂组分为0.2%H3BO3+2.0%Li2CO3+2.0%AlF3(质量分数)。所制备的(Ce0.67,Tb0.33)MgAl11O19荧光粉样品具有较为规则的形貌,且发光亮度与(Ce0.67,Tb0.33)MgAl11O19现有商用粉的比值为103:100。     

Ca2GeO4 ∶Eu3+ 的电子结构和紫外-真空紫外发光特性的研究

采用高温固相法合成了发光材料Ca₂GeO₄ ∶Eu³⁺ ,并详细研究了其紫外-真空紫外发光特性. 发现并解释了Eu³⁺ 离子在空气中的自还原以及在不同波长激发下的颜色转换现象. Ca₂GeO₄ ∶Eu³⁺ 在163—230和301,466 nm处具有强激发带,表明Ca₂GeO₄ ∶Eu³⁺ 关键词： 2GeO₄ ∶Eu³⁺')" href="#">Ca₂GeO₄ ∶Eu³⁺ 光致发光机理 空气中自还原 颜色转换     

Photoluminescence and persistent luminescence properties of non-doped and Ti4+-doped Mg2SnO4 phosphors

Mg₂SnO₄ exhibits green photoluminescence and persistent luminescence, which originate from oxygen vacancies. When Ti⁴⁺ ions were doped, an interesting Mg₂SnO₄:Ti⁴⁺ phosphor with bluish white photoluminescence under ultraviolet irradiation and with green persistent luminescence was first obtained. Our investigation reveals that two emission centres exist in Mg₂SnO₄:Ti⁴⁺. The centres responsible for the green emission are considered to be the F centres (oxygen vacancies) and the blue centres are the TiO₆ complex. Trap clusters in the band gap with different depths, such as [Sn_Mg^‥—O_i^″], [Sn_Mg^‥—V_O^·], [Sn_Mg^‥—V_O^×] and Mg_Sn^″, correspond to the components at 85 ℃, 146 ℃ and 213 ℃ of the thermoluminescence curve.     

Photoluminescence degradation mechanism of BaMgAl10O17：Eu2＋ phosphor by vacuum ultraviolet irradiation

<正>A real high power vacuum ultraviolet light source is applied to the investigation on the vacuum ultraviolet irradiation degradation of BaMgA₁₀O₁₇:Eu²⁺ phosphor.The degradations of emission intensity and color quality of the sample are clearly observed after irradiation.It reveals that the oxidation of Eu²⁺ during irradiation is partly responsible for the degradations.The excitation and absorption spectra show that some traps generated during irradiation have negative influence on the luminescence of sample and these traps have been identified as positively charged oxygen vacancies by positron annihilation.The investigations on host emission and decay curve further confirm that these oxygen vacancies are involved in the perturbation of energy transfer from the host to Eu²⁺ and finally result in the degradation.