铁电氧化物一维单晶纳米材料的基础问题研究

The fundamental scientific problems concerning growth, synthesis and funtional tailoring in one-dimensional (1D) single-crystal ferroelectric oxide nanomaterials will be explored intensively, and supported by this program. The research conducts the nanomaterial nucleate-growth process and its mechanism , and a range of novel concept and methods , such as selective surfactant absorption, external field and doping, are employed to materialize the controlled preparation of the nanomaterials. Intrinsic piezoelectricity, ferroelectricity and their evolution will be pursued from the crystalline level, surfaces to the atomic level by means of in-situ high resolution transmission electron microscope (HRTEM),aberration-corrected HRTEM and atomic force microscope (AFM). Based on this, the size effect of the nanomaterials and the physical mechanism underneath will also be illustrated, and thus the relationship among the nanomaterial growth, microstructure and properties will be uncovered. Furthermore, polarization field,the physical property and size effect of the materials will be explored with an applied external field effect, including environmental atmosphere, external stress and electric field, leading to a comprehensive understanding of the material functional tailoring by applying the external fields. The effect of doping and phase transformation on the material physical property is also investigated to optimize its applied functions. Possible applications of such 1D single-crystal ferroelectric oxide nanomaterials in novel nanodevices will be explored and discussed.

紧密围绕铁电氧化物一维单晶纳米材料的生长机制、外场作用和性能调控等关键科学问题深入开展基础研究；研究铁电氧化物一维单晶纳米材料的成核-生长过程，揭示其生长机制，通过选择性表面吸附、外场以及掺杂等创新思路和方法调控其生长过程，实现铁电氧化物一维单晶纳米材料的可控制备；利用原位高分辨电镜、球差校正电镜和原子力显微镜等手段从晶体结构、表面以及原子尺度上研究铁电氧化物一维单晶纳米材料的本征压电、铁电性能及其规律，阐明尺寸效应及其物理机制，建立晶体生长-微结构-性能的关联；研究外场（气氛、应力和电场等）对铁电氧化物一维单晶纳米材料微结构、极化场和物理性能的影响规律与尺寸效应，获得外场作用对材料物性调制的规律；研究掺杂和相变对铁电氧化物一维单晶纳米材料物理性能的调控，优化材料性能；探索这类材料在新型纳米器件中的应用。

本项目重点围绕铁电氧化物一维单晶纳米材料生长、制备和性能深入开展基础研究。系统研究并揭示了ABO3型前钙钛矿和钙钛矿氧化物单晶或类单晶纳米纤维的取向聚集(Oriented attachment, OA)生长机制，发展了一类单晶或类单晶ABO3型纳米纤维的可控制备技术，实现了纳米纤维的尺寸和形貌的调控；结合理论和实验研究发现了前钙钛矿PbTiO3纳米纤维新颖的铁电、光学和磁学性能，研究揭示了氧无序驱动的前钙钛矿到钙钛矿单晶纳米纤维的固态相变机制，发现了单晶介孔钙钛矿PbTiO3纳米纤维奇特零膨胀现象，阐明了其铁电极化起源；研究了一系列稀土元素掺杂的前钙钛矿和钙钛矿氧化物纳米纤维中掺杂位置、铁电极化以及温度等对上转换荧光的调控作用，探索了这类材料在药物缓释中的应用；提出并发展了铁电极化调控的氧化物异质结生长新技术，获得了原子级平整的单晶氧化物异质结，实现了极化调控的生长、界面结构与载流子分离。本项目发表包括Nano Energy, Small, ACS Appl. Mater. Interfaces, J.Mater. Chem(A, B,C)在内的标注SCI论文61篇，其中影响因子大于5.0的SCI论文11篇，授权国家发明专利16项。本项目的实施大幅提高了铁电氧化物一维单晶纳米材料的基础研究水平，丰富和拓展了钙钛矿氧化物单晶纳米材料体系及其功能性，为发展新型光电器件与催化材料提供了契机。