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采用水解法制备不同W掺杂量的VO2(M)粉体。借助于X射线衍射仪、Fourier变换红外谱、差示扫描量热仪、X射线光电子谱仪和X射线精细结构谱对粉体的成分和结构进行表征。结果表明,W6+进入VO2晶格,形成固溶体V4+1-3xV3+2xWxO2。W掺杂降低了VO2(M)的相变温度,相变温度与W掺杂量在一定范围内成线性关系,掺杂效率约为18℃/1%(摩尔分数)。掺杂的大半径W原子部分替换了VO2(M)晶格中的V原子,晶格膨胀畸变产生的压应力通过共享顶点O,沿着W—O—V链传递到邻近的次晶格,造成V—O键键长变化,促使V周围的氧分布对称性随W掺杂量的增加而增大。当W掺杂量增大至2.5%时,单斜结构中的V—O1键和V—V1a键伸长,V—O2键和V—V1b键缩短,V—O1和V—O2峰合并成金红石结构的V—O峰,V—V1a峰和V—V1b峰合并成金红石结构的V—V1峰,即样品已转变为金红石结构。
VO2 (M) powders with different W doping levels were prepared by hydrolysis. The composition and structure of the powders were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry, X-ray photoelectron spectroscopy and X-ray fine structure spectroscopy. The results show that W6 + enters the VO2 lattice and forms solid solution V4 + 1-3xV3 + 2xWxO2. W doping decreases the phase transition temperature of VO2 (M). The phase transition temperature and W doping amount have a linear relationship within a certain range. The doping efficiency is about 18 ℃ / 1% (mole fraction). The doped large-radius W atoms partially replace the V atoms in the VO2 (M) lattice. The compressive stress generated by the lattice expansion distortion is transmitted to the adjacent sub-lattice along the W-O-V chain by sharing the vertex O, Resulting in V-O bond length changes, to promote the symmetry of the distribution of oxygen V with increasing W doping increases. When W doping amount increases to 2.5%, the V-O1 bond and the V-V1a bond elongate in the monoclinic structure, the V-O2 bond and V-V1b bond are shortened, and the V-O1 and V-O2 peaks are combined into gold The V-O peak of the redstone structure, the V-V1a peak and the V-V1b peak merge into the V-V1 peak of the rutile structure, that is, the sample has been transformed into a rutile structure.