水热条件下有机分子调控钛酸铅铁电纳米结构的高度取向生长(英文)

Highly oriented growth of PbTiO_3 ferroelectric nanostructure directed by organic molecules under hydrothermal condition

通过在水热过程中引入无水乙醇、油酸、油胺和聚丙烯酸4种有机分子以实现对钙钛矿相钛酸铅纳米结构晶体生长的调控。利用XRD、SEM、Raman、TEM和HRTEM对水热合成的粉体进行系统的表征和分析。对应4种有机分子,水热合成的钙钛矿钛酸铅粉体分别为面包圈状微米片、正方形纳米片、碎裂立方体和不规则纳米片团聚结构。研究结果表明,水热体系中无水乙醇有机溶剂的引入对面包圈状单晶微米片的形成起很大的促进作用,所形成的微米片边长约为5～20μm,厚度约为150 nm。XRD、TEM和HRTEM的微结构分析表明,钛酸铅单晶微米片在形成过程中经历了一个沿着ab晶面的强烈取向生长机制。基于实验结果,作者提出了钛酸铅微米片状的形成机理,即钛酸铅微米片状结构的形成原因可能是无水乙醇分子选择性地吸附在钙钛矿相钛酸铅{001}晶面上,并促进了钛酸铅晶核的选择性沉积。

Four organic molecules including ethyl alcohol, oleic acid, oleylamine and poly acrylic acid have been introduced into a hydrothermal process to modify the crystal growth of pcrovskite lead titanate （PbTiO3 , PT） nanostructurcs. The resulting products were systematically characterized by using X-ray powder diffraction （XRD）, scanning electron microscope （SEM）, Raman scattering spectroseop, transmission electron microscope （TEM） and high-resolution TEM （HRTEM）. Corresponding morphology of the samples changes from donut-like microplates, square nanoplates, broken cubes to aggregated nanoplates. The results indicated that the introduction of 10 mL ethyl alcohol was particularly favourable to form donut-like single-crystal mieroplates of PT with an average lateral length of about 5 - 20 μm and a thickness of about 150 nm. XRD, TEM and HRTEM results suggested that the donut-like single-crystal mieroplates of PT probably experience a strong preferential growth along ab crystal planar via an oriented attachment mechanism. It is proposed that a selective absorbance of ethyl alcohol molecules on the { 001 } planes of tetragonal perovksite PT plays a key role in a preferred precipitation of crystal nucleates and thus the formation of donut-like microplates.