溶胶凝胶法制备的La_(2–x)M_xCuO_(4–δ)晶体的UV–Vis–NIR光学性质(英文)  

Optical Properties in the UV–Vis–NIR Region of La_(2-x)M_xCuO_(4-δ) Crystallites Synthesized by Sol–Gel Process

作　　者：李意峰[1] 黄剑锋[1] 曹丽云[1] 吴建鹏[1] 

机构地区：[1]陕西科技大学,教育部轻化工助剂化学与技术重点实验室,西安710021

出　　处：《硅酸盐学报》2012年第3期432-435,共4页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金(50942047,51102196);陕西省自然科学基金(2010 JM6001);陕西科技大学科研创新团队基金(TD09–05)及陕西科技大学研究生创新基金资助项目

摘　　要：采用溶胶–凝胶法制备了La2CuO4和La2–xMxCuO4–δ(M=Ca、Sr和Ba)晶体。通过X射线衍射、扫描电子显微镜和紫外–可见–近红外光谱对La2CuO4和La2–xMxCuO4–δ(x=0.1)粉体进行了测试和表征。结果表明,700℃煅烧2 h,可以获得单相La2CuO4和La2–xMxCuO4–δ(M=Ca、Sr和Ba),且均为正交晶型结构。光谱性质表明,La2CuO4和La2–xMxCuO4–δ系化合物在紫外–可见和近红外范围都有较宽的吸收。La2CuO4、La1.9Ca0.1CuO4–δ、La1.9Sr0.1CuO4–δ和La1.9Ba0.1CuO4–δ的带隙分别为1.44、1.57、1.40 eV和1.37 eV。带隙的变化是由于碱土金属离子的半径不同,造成对键的不匹配性的影响不同而引起的。The La2CuO4 and La2–xMxCuO4–δ(M = Ca,Sr and Ba) crystallites were prepared via a sol–gel process.The as-prepared La2CuO4 and La2–xMxCuO4–δ crystallites were characterized by X-ray diffraction,scanning electron microscope and ultravio-let–visible–near infrared(UV–Vis–NIR) spectroscopy.The results show that the pure La2CuO4 and La2–xMxCuO4–δ(x = 0.1) crystal-lites can be obtained after the calcination at 700 ℃ for 2 h,and the samples exhibit an orthogonal crystal structure.The La2CuO4 and La2–xMxCuO4–δ both had a broad absorption in the UV–Vis region and the NIR region,and the band gaps of La2CuO4,La1.9Ca0.1CuO4–δ,La1.9Sr0.1CuO4–δ and La1.9Ba0.1CuO4–δ were 1.44,1.57,1.40 and 1.37 eV,respectively.The variation of the band gap was attributed to the different radii of alkaline earth ions,having an effect on the bond-mismatch that caused the corresponding changes.

关 键 词：铜酸镧 碱土金属取代铜酸镧 紫外–可见–近红外光谱 带隙 溶胶–凝胶法 

分 类 号：TB34[一般工业技术—材料科学与工程]