Quantum-Dot-Based Fluorescence Sensing

Quantum dots are artificial atom clusters that can be used in a variety of photonic devices due to their size-dependent absorption and emission characteristics. Compared to the quantum dots, many of the organic dyes suffer from self-quenching, photobleaching, small Stokes shift, short-term aqueous stability, and short excited state fluorescence lifetime [3, 166]. Quantum dots show tunable optical properties, simultaneous excitation of multiple fluorescence colors, large surface areas, and excellent photostability. The intense emission of the quantum dots makes them especially useful in various optical sensing applications. The surface passivation techniques help to improve the electro-optic properties of quantum dots and reduce their toxicity. Quantum dots have found application in a wide variety of areas like displays, photovoltaics, lasers, sensing, etc. In particular, the application of quantum dots in sensing has been discussed in detail in this chapter. Because of their unique characteristics like photostability, single molecule detection, NIR emission, and long-term sensitivity, quantum dots are increasingly replacing organic dyes in sensing applications. Today, the detection of more biomolecules and DNA tracking are both made possible by quantum-dot sensing. It promises pH sensing, ratiometric fluorescence sensing, and a multi-color probing method. According to recent advancements in quantum-dot-based sensing, the management of cancer may soon be profoundly impacted by quantum dots [46, 117].