掺杂型Ⅰ-Ⅲ-Ⅵ族多元量子点的制备及应用研究进展

Synthesis and Application of DopedⅠ-Ⅲ-ⅥMultiple Quantum Dots

Ⅰ-Ⅲ-Ⅵ族多元量子点具有粒径尺寸小、半峰宽较宽、Stokes位移大、抗光漂白能力强、绿色环保等优异的物理化学性质,通过改变其化学成分可以实现发射范围在可见光到近红外光区域连续调谐,同时避免了Cd、Hg、Pb等重金属元素和Se、Te、P、As等剧毒阴离子的使用。上述优点使其成为替代传统二元量子点的理想材料,因此在太阳能电池、发光二极管、光探测器、生物成像等领域具有广阔的应用前景。与二元量子点相比,多元量子点由于含有多种不同类型的金属离子,存在金属离子反应速率不同的问题,使得晶体内部缺陷较多,因此荧光性能仍有待提高。掺杂过渡金属离子(例如Zn 2+、Mn 2+或Cu+)可有效调控多元量子点的带隙宽度,不仅可增大量子点的Stokes位移,还能促进辐射复合,从而有效拓宽发光范围,提高量子产率。本文详细阐述了掺杂型Ⅰ-Ⅲ-Ⅵ族多元量子点的发光机理,分别介绍了有机相和水相合成法制备该类型量子点的特点,通过有机相合成的多元量子点具有结晶性好、荧光量子产率高的优点,而水相合成的多元量子点具有安全环保、生物相容性好等明显优势。同时,本文综述了过渡金属离子掺杂和共掺杂对多元量子点带隙宽度、可见光吸收范围和荧光强度的影响,最后总结了该类量子点在光电、生物医药和荧光传感器等领域的应用进展。

TheⅠ-Ⅲ-Ⅵmultiple quantum dots(QDs)have excellent physicochemical properties such as small particle size,broad half-peak width,large Stokes shift,anti-photobleaching stability,environment friendliness,and their emission range can be continuously tuned in the visible to near-infrared light region by changing the chemical composition.Moreover,they can avoid the use of heavy metal elements such as Cd,Hg and Pb and highly toxic anions,i.e.Se,Te,P and As.These advantages make them promising candidates to replace traditional binary QDs in the fields of solar cells,light-emitting diodes,photodetectors,bioimaging,etc.Compared with the binary QDs,the multiple QDs contain many different types of metal ions and have the problem of different reaction rates between metal ions,causing more defects inside the crystal.Therefore,its fluorescence performance still needs to be improved.The doping of transition metal ions(e.g.Zn 2+,Mn 2+or Cu+)can effectively modulate the band gap width of multiple QDs,which can not only increase the Stokes shift of QDs,but also promote the radiation recombination,thus effectively broadening the luminescence range and increasing the quantum yield.This paper elaborates the luminescence mechanism of dopedⅠ-Ⅲ-Ⅵmultiple QDs,and introduces the characteristics of organic phase and aqueous phase preparation of this type of QDs,respectively.Multiple QDs synthesized by organic phase have the advantages of good crystallinity and high fluorescence quantum yield,while those synthesized by aqueous phase also have obvious advantages such as safety,environmental friendliness and good biocompatibility.Meanwhile,the paper reviews the effects of transition metal ion doping and co-doping on the band gap width,visible light absorption range and fluorescence intensity of multiples QDs.Finally,the progress of doped multiple QDs in the fields of optoelectronic,biomedical applications and fluorescences is also summarized.