ABSTRACT
This chapter explains the synthesis, properties, and applications of functionalized quantum dots. Nanotechnology has recently gained a lot of attention in various fields of science due to the diverse properties of nanoparticles. These nanoparticles are divided broadly into three categories on the basis of their dimensions, i.e. zero, one, two, and three dimensions. Among these categories, zero-dimensional nanoparticles, i.e. quantum dots, display exceptional optical, electronic, and surface behavior due to their unique charge distribution between the lattice structure. These unmatched properties of quantum dots make it so special in diverse fields of science and technology but the major challenge in quantum dots chemistry is the control of size in the zero dimension. The most commonly used methodology for the synthesis of quantum dots is the bottom-up approach, as the top-down approach carries several disadvantages like less control over shape and size, an increase in the number of defective states, poor quantum yields, etc. This chapter explains the various methodologies adopted for the synthesis of quantum dots. In the case of bottom-up approach, different routes carry different advantages and disadvantages, e.g. the microemulsion technique provides good control over the size of quantum dots but leads to a poor yield of quantum dots. Similarly, ion exchange methodology provides ~99.9% yield but the reaction time is very long. In addition, hydrothermal technology is providing an alternative but the condition for the synthesis is quite drastic (high temperature). One can design the synthetic route based on the property and the application required, as well as the conditions provided. To further improve the applicability as well as other properties like water stability, high quantum yield, low toxicity, chemically stability, etc., surface engineering of the quantum dots is required. The surface modification of quantum dots enhances its applicability in chemical/ion sensing, target drug delivery, etc. Therefore, the present chapter focuses on the background, properties, synthesis, and application of quantum dots.
