Effects of heat treatment conditions and Y-doping on structure and phase transition temperature of VO2 powders

热处理条件和Y掺杂对VO2粉体结构及相变温度的影响

The VO2 powders were prepared by hydrothermal synthesis.The effects of heat treatment conditions and Y-doping on the structure and phase transition temperature of VO2 were studied.The XRD,SEM and TEM results show that the heat treatment temperature has a significant effect on the crystal transformation of VO2 precursor.Increasing temperature is conducive to the transformation of precursor VO2(B)to ultrafine VO2(M).The Y-doping affects the structure of VO2.Y^3+can occupy the lattice position of V4+to form YVO4 solid solution,which can increase the cell parameters of VO2.Due to the lattice deformation caused by Y-doping,the aggregation of particles is prevented,and the grain is refined obviously.DSC curves show that Y-doping can reduce the phase transition temperature of VO2(M).After adding 9 at.%Y,the phase transition temperature can be reduced from 68.3 to 61.3℃.

以水热合成法制备VO2粉体,研究热处理条件和Y掺杂对VO2结构及相变温度的影响。XRD、SEM和TEM结果表明:热处理温度对VO2前驱体的晶型转变影响显著,升高温度,有助于VO2(B)向VO2(M)转变。Y掺杂对VO2结构产生影响,Y^3+可以占据V^4+晶格点阵位置,形成YVO4固溶体,从而增大VO2的晶胞参数。Y掺杂导致的晶格变形能阻止颗粒的聚集,因此,Y掺杂具有一定的细化晶粒作用。DSC曲线表明,Y掺杂可以降低VO2(M)的相变温度,当Y掺杂浓度为9%(摩尔分数)时,相变温度可由未掺杂的68.3℃降低到61.3℃。