CuInS2/CdS基掺杂纳米晶的晶体结构、光谱性质及性能调控研究

多功能纳米晶的制备、性能及其应用是材料、化学、能源、生物医学等领域十分关注的课题之一。基于掺杂调控纳米晶生长和性能的思想,发展了纳米晶修饰和复合的概念和技术,使用绿色安全的化学溶液法结合外延生长技术合成了巯基丙酸(MPA)包覆的掺杂CuInS₂/CdS基纳米晶材料。通过适当调整掺杂异价离子的种类,实现了对CuInS₂/CdS基纳米晶显微结构和性能的调控,获得了具有特定相结构、组分、尺度和光学性能(吸收性质、光学带隙、发光强度)的纳米晶。存在于基质晶体中不同金属掺杂离子,会造成半导体的禁带中间产生掺杂能级,导致二次跃迁,进而产物体现出不同的禁带宽度。掺杂Co ²⁺、Fe ²⁺、Er ³⁺离子的CuInS₂/CdS纳米晶光致发光(PL)峰强度降低明显,这是由于Co ²⁺、Fe ²⁺、Er ³⁺离子掺杂有效地抑制了空穴-电子对的复合,降低了纳米晶的光生电子-空穴复合几率,使得其光催化活性得到增强。这些半导体纳米材料在光催化、能量转换与储存方面具有良好的应用潜力。

Crystal structure,spectral properties and performance tailoring of CuInS2/CdS based doped colloidal nanocrystals

The preparation,properties and applications of multifunctional nanocrystals are one of the topics of great concern in the fields of materials,chemistry,energy and biomedicine.Based on the idea of doping to regulate the growth and performance of nanocrystals,the concept and technology of modification and composite of nanocrystals were developed,and mercaptopropionic acid(MPA)-coated CuInS₂/CdS based nanocrystals were synthesized by a green and safe chemical solution protocol combined with an epitaxial growth technology.The microstructures and properties of CuInS₂/CdS based nanocrystals were controlled by adjusting the types of doping hetervalent ions,and the nanocrystals with specific phase structure,component,size and optical properties(absorption property,optical band gap,luminescence intensity)were obtained.The presence of different metal ions in the matrix crystal will cause the doped energy level in the middle of the semiconductor bandgap,leading to the secondary transition,and then the products will reflect different bandgap width.The peak intensities of CuInS₂/CdS nanocrystals doped with Co ²⁺,Fe ²⁺and Er ³⁺ions decrease significantly,which is due to the fact that Co ²⁺,Fe ²⁺and Er ³⁺ions doping effectively inhibits hole-electron pair recombination,reduces the probability of photoelectron-hole recombination of nanocrystals,and enhances their photocatalytic activity.These semiconductor nanomaterials have good application potential in photocatalysis,energy conversion and storage.