等级状CdS树枝晶的形貌控制及生长机理

Morphology-Controlling and Growth Mechanism of Hierarchical CdS Dendrites

以聚乙烯醇(PVA)作为表面修饰剂,采用水热法在180℃下于Cd2+-硫脲络合体系中合成了大量的等级状CdS树枝晶.用扫描电镜研究发现,合成的这些CdS晶体具有规则的树枝状形貌,X射线衍射图谱显示这些产物具有六方铅锌矿结构.研究表明:在晶体生长中,PVA分子在CdS晶体不同晶面的选择吸附对其取向生长有强化作用,从而有助于树枝晶的形成,但过量PVA的空间位阻效应及其交联作用对CdS树枝晶的形成有不利的影响.

Hierarchical CdS dendrites were synthesized at 180 ℃ in the Cd2＋-thiourea chelate system by a hydrothermal method, using polyvinyl alcohol （PVA） as a surface modifier, The products were characterized by means of X-ray diffraction （XRD） and scanning electron microscope （SEM）. The results indicate that the dendrites are hexagonal CdS and the selective adsorption of PVA onto different faces plays an important role in the growth of the hierarchical CdS dendrites. But the steric hindrance effects and crossinking role of superfluous PVA are adverse to the growth of dendrites.