**4. Optical properties**

Particle size is one of the most important aspects that can affect the optical properties of quantum dots. Of course, various other factors such as the shape and composition of quantum dots, as well as the methods and materials used in the synthesis of these particles also affect the optical properties and frequency of fluorescent light emitted or absorbed by these nanocrystals [11]. Therefore, by manipulating each of the effective factors, special quantum dots with specific properties can be prepared for different purposes.
