InP/ZnS Quantum Dots

InP/ZnS Quantum Dots List

Quantum dots are a class of nanomaterials composed of II-VI or III-V group elements. Quantum dots have quantum size effect, and their optical properties vary with the change of particle size. The luminescence efficiency of quantum dots is also greatly improved compared with that of bulk materials. Among the numerous quantum dots, Cd-based quantum dots have been studied most deeply. However, the use of heavy metals has brought great problems to the commercial production. Among all alternative materials for Cd-based quantum dots, InP quantum dots are considered as the most promising alternative materials. The reasons are that InP quantum dots have a band gap that is similar to Cd-based quantum dots and the whole visible range can be covered with the properties of band gap tunability. However, the surface defects of InP quantum dots will seriously affect the optical properties. In order to solve this problem, semiconductor shells with large gap width are generally used to enhance the luminescence of InP quantum dots. ZnS is a commonly used coating material for InP quantum dots. As a kind of green quantum dots, InP/ZnS quantum dots have a broad application prospect.

Figure 1. An example of InP/ZnS quantum dot.

Applications:

• White light emitting diode (LED) field: White light emitting diode (LED) is known as the fourth generation of lighting source. As a new generation of solid-state light source, white LED has many advantages, including low energy consumption, high luminous intensity, high efficiency, excellent vibration resistance, low voltage drive and the others. With the properties of high luminous efficiency, long life and high color rendering, quantum dots phosphors are widely used in the field of white LED in recent years. Among them, InP/ZnS quantum dots are a new type quantum dots with low toxicity, low cost, high color rendering index and good stability, and they have broad application prospects in this field.
• Biomedical field: InP/ZnS quantum dots can be designed as near infrared quantum dots. Near infrared InP/ZnS quantum dots can successfully avoid spontaneous fluorescence of organisms. Moreover, near infrared InP/ZnS quantum dots can greatly improve the penetration ability of biological tissues. At present, near infrared InP/ZnS quantum dots have been widely used in biomedical fields, including medical diagnosis, bioluminescence labeling, cancer cell imaging and the others.

Figure 2. An example of InP/ZnS quantum dots used in cell imaging.

• The others: InP/ZnS quantum dots are also widely used in other fields including detection, laser and the others. For example, parathion is one of the most representative organophosphorus pesticides. Fluorescent probe can be designed based on InP/ZnS quantum dots to detect the concentration of parathion, which has high selectivity and sensitivity.

Classification:

According to the solubility, InP/ZnS quantum dots can be divided into water-soluble InP/ZnS quantum dots and non-water-soluble InP/ZnS quantum dots.

• Water-soluble InP/ZnS quantum dots: Water-soluble InP/ZnS quantum dots have excellent dispersibility in aqueous phase solution, which is beneficent for biological applications.
• Non-water-soluble InP/ZnS quantum dots: InP/ZnS quantum dots also can be designed to non-water-soluble. According to the demands, the fluorescent properties can be adjusted.

References

1. Bowen Zhang, Dengkui Wang, Xuan Fang, et al. Study on the Luminescence Properties of InP/ZnS Quantum Dot[J]. Material Sciences, 2018, 8(3), 131-136.
2. Hussain S, Won N, Nam J, et al. One-pot fabrication of high-quality InP/ZnS (core/shell) quantum dots and their application to cellular imaging[J]. Chemphyschem, 2010, 10(9-10):1466-1470.