CdSe/ZnS Quantum Dots List
The concept of quantum dots was first proposed by Esaki in 1975, in which CdSe/ZnS quantum dots is an important branch. CdSe/ZnS quantum dots is a kind of nanoscale quantum dots with core-shell structure, in which CdSe is the core material and ZnS is the shell material. The optical properties of CdSe/ZnS quantum dots are mainly determined by the CdSe core material. The size of CdSe/ZnS quantum dots is in the nanoscale range, and they have many unique optical properties. First, the excitation spectrum of CdSe/ZnS quantum dots is wide, and the continuous emission spectrum is narrow and symmetric. Second, the wavelength of the fluorescence spectrum of CdSe/ZnS quantum dots can be adjusted by changing the composition or radius size. Third, CdSe/ZnS quantum dots are highly anti-photo-bleach, and the fluorescence signal can last a long time. Fourth, the Stokes shift of CdSe/ZnS quantum dots is wide, which is favorable for detection field.
- Fluorescent probe field: Compared with traditional detection methods, fluorescent probes are widely used because of their advantages such as high selectivity, high sensitivity, rapid response, low cost and easy operation. Due to the unique physicochemical properties, such as high luminous efficiency, adjustable luminous wavelength, good stability and easy surface modification, CdSe/ZnS quantum dots have attracted much attention in the field of fluorescent probe. For example, hydrogen peroxide is a very important reactive oxygen species, which is widely used in industry, biomedicine, food and other fields. However, excessive hydrogen peroxide will lead to environmental pollution and harm human health. The fluorescent probe constructed by surface modified CdSe/ZnS quantum dots can realize the detection of hydrogen peroxide.
Figure 1. An example of CdSe/ZnS quantum dot applied as a fluorescent probe.
- Biomedical field: CdSe/ZnS quantum dots have been widely applied in biomedical field, mainly in the following aspects. First, CdSe/ZnS quantum dots can be applied as fluorescent markers in biological cells. Second, quantum dots can be used in in vivo imaging. Because of the characteristics of strong emission spectrum, high quantum yield and light bleaching resistance, quantum dots can simultaneously meet the requirements of high sensitivity detection and long-term dynamic tracking monitoring, which is an ideal marker for in vivo targeted tracer and dynamic imaging. Third, in organisms, CdSe/ZnS quantum dots can react with oxygen molecules in cell molecules to produce toxic singlet oxygen, which can kill cancer cells. Therefore, CdSe/ZnS quantum dots are also often used in photodynamic therapy.
Figure 2. Examples of water-soluble CdSe/ZnS quantum dots applied in biomedical field.
- The others: CdSe/ZnS quantum dots is also can be used in many other fields, such as quantum dot computers, optical communications, lighting sources, pharmacology and other fields.
According to the solubility, CdSe/ZnS quantum dots can be divided into water-soluble CdSe/ZnS quantum dots and non-water-soluble CdSe/ZnS quantum dots.
- Water-soluble CdSe/ZnS quantum dots: The water solubility of this type quantum dots is excellent, and they have a promising application prospect in biological field.
- Non-water-soluble CdSe/ZnS quantum dots: After modified by hydrophobic material, non-water-soluble CdSe/ZnS quantum dots can be obtained. This type quantum dots can be applied in many fields.
- Xu, Hu, Li, et al. p-Aminothiophenol-coated CdSe/ZnS quantum dots as a turn-on fluorescent probe for pH detection in aqueous media[J].Talanta: The International Journal of Pure and Applied Analytical Chemistry, 2017.
- Ramalingam G, Saravanan K V, Vizhi T K, et al. Synthesis of water-soluble and bio-taggable CdSe@ZnS quantum dots[J]. Rsc Advances, 2018, 8(16):8516-8527.