基于密度泛函理论(DFT)的第一性原理,研究了氟磷灰石、氯磷灰石和羟基磷灰石的电子结构,讨论了不同通道离子(F-、Cl-、OH-)对磷灰石电子结构的影响。能带分析表明:氟磷灰石、氯磷灰石和羟基磷灰石均为绝缘体,其带宽分别为5.600、5.384和...基于密度泛函理论(DFT)的第一性原理,研究了氟磷灰石、氯磷灰石和羟基磷灰石的电子结构,讨论了不同通道离子(F-、Cl-、OH-)对磷灰石电子结构的影响。能带分析表明:氟磷灰石、氯磷灰石和羟基磷灰石均为绝缘体,其带宽分别为5.600、5.384和3.577 e V。态密度分析表明:通道离子对3种磷灰石的态密度影响较大,氟磷灰石与氯磷灰石导带部分有Ca1 3d轨道和Ca2 3d轨道的贡献;羟基磷灰石态密度导带部分仅有Ca2 3d轨道的贡献,导致Ca2还原性降低;羟基磷灰石态密度向低能级方向移动,形成新的深部价带;Cl的态密度较F的态密度向高能级方向移动,导致形成新的中部价带-12.5~14.0 e V,该价带仅由Cl 3s轨道组成。Mulliken电荷布居及键布居表明:F得电荷能力强于Cl,主要是F的2p轨道得电荷能力强于Cl的3p轨道;3种磷灰石中的O—P键布居接近且均较大,共价性较强,F—Ca与Cl—Ca布居接近,但F—Ca键长小于Cl—Ca键长,F—Ca结合作用强于Cl—Ca。展开更多
As an emerging host phosphor material, barium chlorapatite （Bas（PO4）3CI）, is attracting growing attention. However, rare earth-doped Bas（PO4）3CI phosphors have mainly been obtained via high temperature-based, en...As an emerging host phosphor material, barium chlorapatite （Bas（PO4）3CI）, is attracting growing attention. However, rare earth-doped Bas（PO4）3CI phosphors have mainly been obtained via high temperature-based, energy-consuming techniques. In this contribution, we developed a straight- forward, facile room-temperature coprecipitation method in the presence of a specific amount of ethylenediaminetetraacetic acid disodium salt that provided Bas（PO4）3CI nanoparticles self-assembled to construct uniform Bas（PO4）3CI nanoassemblies （diameter： 80-120 nm） as well as rare earth Tb3＋- doped Bas（PO4）3CI：xTb3＋ nanophosphors. The nanoassemblies were transparent within the ultraviolet and visible spectral range. The Bas（PO4）3CI：xTb3＋ nanophosphors exhibited four emission peaks under 228-nm excitation, and the optimal doping amount of Tb3＋ was 4.0%. In contrast to traditional energy-consuming, high-temperature techniques, the facile room-temperature coprecipitation method developed here represents an attractive alternative route to obtain uniform Ba5（PO4）3CI nanoassemblies and Bas（PO4）3CI：xTb3＋ nanopbosphors that are candidate luminescent hosts.展开更多
文摘基于密度泛函理论(DFT)的第一性原理,研究了氟磷灰石、氯磷灰石和羟基磷灰石的电子结构,讨论了不同通道离子(F-、Cl-、OH-)对磷灰石电子结构的影响。能带分析表明:氟磷灰石、氯磷灰石和羟基磷灰石均为绝缘体,其带宽分别为5.600、5.384和3.577 e V。态密度分析表明:通道离子对3种磷灰石的态密度影响较大,氟磷灰石与氯磷灰石导带部分有Ca1 3d轨道和Ca2 3d轨道的贡献;羟基磷灰石态密度导带部分仅有Ca2 3d轨道的贡献,导致Ca2还原性降低;羟基磷灰石态密度向低能级方向移动,形成新的深部价带;Cl的态密度较F的态密度向高能级方向移动,导致形成新的中部价带-12.5~14.0 e V,该价带仅由Cl 3s轨道组成。Mulliken电荷布居及键布居表明:F得电荷能力强于Cl,主要是F的2p轨道得电荷能力强于Cl的3p轨道;3种磷灰石中的O—P键布居接近且均较大,共价性较强,F—Ca与Cl—Ca布居接近,但F—Ca键长小于Cl—Ca键长,F—Ca结合作用强于Cl—Ca。
基金This work was supported by the National Natural Science Foundation of China （No. 21276141） and the State Key Laboratory of Chemical Engineering, China （No. SKL-ChE-15A03）.
文摘As an emerging host phosphor material, barium chlorapatite （Bas（PO4）3CI）, is attracting growing attention. However, rare earth-doped Bas（PO4）3CI phosphors have mainly been obtained via high temperature-based, energy-consuming techniques. In this contribution, we developed a straight- forward, facile room-temperature coprecipitation method in the presence of a specific amount of ethylenediaminetetraacetic acid disodium salt that provided Bas（PO4）3CI nanoparticles self-assembled to construct uniform Bas（PO4）3CI nanoassemblies （diameter： 80-120 nm） as well as rare earth Tb3＋- doped Bas（PO4）3CI：xTb3＋ nanophosphors. The nanoassemblies were transparent within the ultraviolet and visible spectral range. The Bas（PO4）3CI：xTb3＋ nanophosphors exhibited four emission peaks under 228-nm excitation, and the optimal doping amount of Tb3＋ was 4.0%. In contrast to traditional energy-consuming, high-temperature techniques, the facile room-temperature coprecipitation method developed here represents an attractive alternative route to obtain uniform Ba5（PO4）3CI nanoassemblies and Bas（PO4）3CI：xTb3＋ nanopbosphors that are candidate luminescent hosts.
