Semiconductor nanocrystals, also known as quantum dots, are tiny particles made from semiconductor materials that range from 1 to 10 nanometers in size. Their small size allows them to exhibit unique optical and electronic properties, which differ from bulk materials. This size-dependent behavior is primarily due to quantum confinement effects, where the movement of electrons is restricted, leading to discrete energy levels. These nanocrystals can emit specific colors of light when excited, making them useful in various applications such as LEDs, solar cells, and biological imaging. Their tunable properties allow for customization based on the desired application, enhancing performance in technologies like displays and sensors.