How Many Electron Traps are formed in Persistent Phosphors?
How Many Electron Traps are formed in Persistent Phosphors?
复制标题
持久性荧光粉中形成了多少个电子陷阱？
DOI：
10.1149/2162-8777/ac2e4e
复制
发表时间：
2021
影响因子：
2.2
通讯作者：
Tanabe Setsuhisa
中科院分区：
文献类型：
--
作者：
Ueda Jumpei;Xu Jian;Takemura Shota;Nakanishi Takayuki;Miyano Shun;Segawa Hiroyo;Tanabe Setsuhisa
持续发光是由由激发光填充的载流子陷阱的电荷载流子脱陷过程引起的。因此，载流子存储容量是决定持续发光强度的重要因素。本文研究了YAGG：Ce？⁺-Yb？⁺透明陶瓷永久荧光粉的电子储存能力，其中Ce？⁺离子为发光中心，Yb？⁺离子为电子陷阱。从Yb？⁺：4F-5d光致变色吸收中心的吸收系数谱和Yb-LiI边XANES谱估算出Yb？⁸电子陷阱中心的数密度约为1.6×10？⁻？⁺：4F-5d，这意味着样品中约12%的Yb？⁺离子在充电后转变为二价态。虽然根据Yb²⁻数密度和Ce⁺：5D⁺：5D₁−4f在520nm处的光子能量计算出0.61J cm⁻³的最大能量密度是持久荧光粉的存储特性，但实际检测到的持久发光的能量密度为0.011 J cm CmPh³。结果表明，Yb~(2+)⁺离子的脱陷电子与空穴俘获的Ce~(2+)⁺离子的复合效率约为几个百分点。
Persistent luminescence is caused by a charge carrier detrapping process from the carrier traps filled by excitation light. Thus, the carrier storage capacity is an important factor in determining the persistent luminescence intensity. Here, the electron storage capacity was investigated in the YAGG: Ce³⁺-Yb³⁺ transparent ceramic persistent phosphor, in which the Ce³⁺ ion is the luminescence center and the Yb³⁺ ion acts as the electron trap. The number density of the Yb²⁺ electron trapping center was estimated to be approximately 1.6× 10¹⁸ ions cm⁻ ³ from the absorption coefficient spectrum of Yb²⁺: 4f–5d photochromic absorption center and the Yb-LIII edge XANES spectrum, which means that approximately 12% of the Yb³⁺ ions in the sample were changed to the divalent state after charging. Although the maximum energy density of 0.61 J cm⁻ ³ was calculated as a storage property of persistent phosphors from the Yb²⁺ number density and the photon energy of Ce³⁺: 5d₁− 4f luminescence at 520 nm, the actual energy density which was detected as persistent luminescence was 0.011 J cm⁻ ³. It is suggested that the recombination efficiency of the detrapped electrons from the Yb²⁺ ions with the hole-trapped Ce³⁺ ions is approximately a few percent.