Due to the tunable Vis-NIR fluorescence and interband fluorescence, β-HgS quantum dots have shown broad application prospects in multi-field such as photoelectric conversion and fluorescence imaging. In this review, the preparation, properties and applications of β-HgS quantum dots are summarized systematically. Firstly, five synthesis methods of β-HgS quantum dots are classified into two categories by solution phase:synthesis in aqueous phase and organic phase. Then, the physical properties of β-HgS quantum dots differing from bulk β-HgS are expounded. Next, the latest applications of β-HgS quantum dots in ion detection, cell imaging, in vivo imaging, light converter and fluorescent ink are summed up. Subsequently, the main two issues existing in the applications of β-HgS quantum dots are pointed out:one is their low photoelectric conversion rate and fluorescence quantum yield for photoelectric device, the other is their poor ability in specific recognition for biomedical fluorescence imaging. Finally, our personal perspectives to solve the problem are outlined that self-assembly aggregates of β-HgS quantum dots could be prepared to improve their photoelectric conversion rate and thermostability; and that chiral biomolecules could be introduced into the surface of β-HgS quantum dots as ligand to obtain chiral β-HgS quantum dots, these chiral β-HgS quantum dots might have potential chiral recognition ability and better biocompatibility which could be used for fluorescence imaging in vitro and in vivo. This review points out a new direction for the development of β-HgS quantum dots.
Contents
1 Introduction
2 Synthesis of β-HgS quantum dots
2.1 Synthesis in organic phase
2.2 Synthesis in aqueous phase
3 Properties of β-HgS quantum dots
3.1 Continuous adjustable fluorescence emission in Vis-NIR band
3.2 Stable electron occupation in the lowest quantum state and interband fluorescence
3.3 Transmission properties for electric magnetic polaron
3.4 High fluorescence quantum yield and good light stability
3.5 Selective recognition ability for metal ion
4 Applications of β-HgS quantum dots
4.1 Heavy metal ion probe
4.2 Cell imaging
4.3 In vivo imaging
4.4 Light converter
4.5 Fluorescent ink
5 Conclusion