II-VI族基半导体二维异质纳米晶的液相法可控合成及光电催化性能研究

The two-dimensional (2D) feature is unique and indispensable to access unprecedented physical, electronic, and chemical properties due to electron confinement in two dimensions. Controllable synthesis 2D II-VI semiconductor based hetero-nanocrystals and achieving the precise modulation of hetero-interface energy band structure are the critical bottlenecks for wide application of 2D II-VI semiconductor hetero-nanocrystals in catalyze, photoelectricity applications. In the proposed project, based on the designing the liquid soft acid-base coordination reactions between host metal ions and the 2D II-VI semiconductor metal ions, achieving the atomically tunable synthesis of hetero-structure CdX/Cu2X, CdX/ZnX 2D lateral hetero-nanocrystals. By utilizing spherical aberration corrected TEM, EXAFS, Kelvin probe force microscope and femtosecond time-resolved transient absorption, based on the studies of extra electrons (n-type doping) or extra holes (p-type doping), mobility of photon-generated carrier, we will achieve the precise ontrol of hetero-interface energy band and doping energy band structure. Exploring the intrinsic microstructure-activity relationship between the interfacial structure, energy band and apparent luminescence performances of the 2D hetero-structured functional nanomaterials systematically, and realizing wider applications of the 2D hetero-structured nanomaterials in the photoelectrocatalysis application.

二维材料因电子高度二维限域化、大比表面积及表面原子高度暴露等优势，展示出新颖的理化特性，成为新能源、光电等应用的理想材料。其组分、晶体工程引起的层内异质界面及掺杂协同调控合成是关键科学问题。本项目拟设计金属离子与二维半导体材料之间的阳离子交换反应，液相法制备层内异质界面可控的二维异质纳米晶（CdX/Cu2X、CdX/ZnX异质纳米结构）并协同实现原子级精度的掺杂。结合球差TEM、EXAFS、KP-FM、时间分辨瞬态吸收谱等高分辨异质界面结构及性能表征，在n型/p型导电、界面载流子传递等光生载流子性质研究基础上，研究其引起的异质界面能带和掺杂能级结构的协同调控、及光电催化等性能的应用。通过原子级精细结构调控引起的“结构-能级-性能”构效关系研究，为其在光电新能源应用奠定新材料基础。

实现过渡金属硫化物（TMDs）二维超薄纳米片可控异价掺杂及横向二维/二维超薄异质纳米片可控构筑，实现掺杂能级和异质界面处能带结构的精确调控，是开发二维材料在光电及能源方面应用的关键科学问题及难题。目前研究仍以同价及不可控间隙位掺杂为主，本项目拟设计不同配位活性的金属离子之间的阳离子交换反应，实现了低温绿色条件下原子级精度异价掺杂的ZnX, CdX, Cu2X超薄纳米片可控制备，获得高效的光致发光，实现了n型/p型导电类型、掺杂能级、掺杂位置和异质界面能带结构调控。在研究其发光机理基础上实现了高效掺杂发光；建立TMDs超薄纳米片的掺杂、导电类型、能带结构、光电性能间的构效关系，为设计发展新型功能TMDs二维纳米材料，为其在光电等方面的应用奠定基础和理论支撑。