Excitons are bound states of an excited electron and hole in a semiconductor, typically created when a photon is absorbed and generates an electron-hole pair. These quasi-particles have properties that are distinct from those of their constituent particles, including their own energy levels and lifetimes. Excitons play a crucial role in many optoelectronic devices, such as solar cells, LEDs, and lasers. Research in the field of excitons aims to understand and manipulate their behavior for the development of more efficient and advanced semiconductor devices. This includes studying exciton dynamics, interactions, and transport in various materials and nanostructures.