Optical Properties of Quantum Dots

The zero-dimension nanomaterials have opened the path for multiple developments in both fundamental and applied sciences in nanoscience and technology. Despite outstanding optical features of quantum dots (QDs), they could not substitute organic dyes because the QDs with heavy metal cores were initially not stable and were hazardous. Since the publications of QDs have grown significantly in the recent decade, numerous advancements have been made in the optical characteristics. Over the years, researchers have developed different approaches to enhance the biocompatibility and optical properties of heavy metal–based QDs. In this context, some other types of QDs, such as carbon quantum dots and graphene quantum dots, revealed excellent biocompatibility, low toxicity, high quantum yield, good photostability, and unique optical properties. Due to these properties, QDs are widely used in the field of nano-biotechnology, such as bio-imaging and biosensing. In this chapter, the optical properties of the QDs are discussed with particular attention to the approaches for tuning the photoluminescence properties, photostability, current theories, and recent developments to understand the photoluminescence mechanism.