Advancements in semiconductor quantum dots: expanding frontiers in optoelectronics, analytical sensing, biomedicine, and catalysis

Semiconductor colloidal quantum dots (CQDs) have emerged as pivotal entities at the forefront of modern nanotechnology, promising revolutionary advancements across various fields including optoelectronics, quantum computing, photocatalysis, and biomedical imaging. In this comprehensive review, we present the latest developments in CQD research offering a profound exploration of their innovative concepts and analyzing recent methodologies and strategies across diverse domains. We first explore the superiority of CQDs over other nanomaterials in the biomedical, optoelectronics, analytical sensing, and photocatalysis domains along with the discovery of CQDs with modern developments. We begin with photophysical properties of CQDs that include size-tunable bandgaps, narrow linewidth emissions, tunable surface chemistry and charge transport, excitation-dependent photoluminescence quantum yields, fluorescence blinking, and "dark fractions". We even address the origin of blinking along with models that govern the fluorescence intermittency within the nanocrystal followed by how the photoluminescence quantum yield (PLQY) of CQDs is hampered by excitation energy and "dark fractions". Then, we delve into the development of exemplary devices featuring a spectrum of architectures, elucidating the recent progress that has led to significant improvements in optoelectronic device efficiency. Furthermore, we examine procedures for converting CQDs into adaptable biological probes for subcellular imaging, drug delivery vehicles, biosensors, and therapeutic agents in the biomedical domain. Additionally, we thoroughly investigate the critical role of ligand selection and synthesis protocols in photocatalysis and analytical sensing, elucidating the underlying photophysical principles in each application. We also discuss ongoing debates, future directions, and emerging trends in the field, aiming to spark increased interest in CQDs and CQD-based composites by showcasing their myriad advantages across various applications. This review serves to underscore the transformative potential of CQDs and stimulate further exploration and innovation in harnessing their unique capabilities. Different applications of semiconductor quantum dots with their unique fundamental properties.