Ag-In-Ga-S Quantum Dots with Narrow Emission and Near-Unity Quantum Yield

Ag-In-Ga-S (AIGS) quantum dots (QDs) have recently emerged as promising, environmentally benign emitters, offering a relatively high color purity and photoluminescence quantum yield (PLQY). Their quaternary composition provides precise control over the emission characteristics across the visible spectrum. Historically, the full potential of AIGS QDs was limited by pervasive bulk and surface defects, resulting in a broad and low-efficiency emission. Recent advances in core composition engineering, interfacial and heterostructure design, and surface-ligand engineering have propelled AIGS QDs into high-performance emitters with spectrally narrow emission and near-unity PLQY. This Review provides a critical examination of the evolution of AIGS QDs from their initial development to the latest breakthroughs, highlighting the key strategies for narrowing emissions, increasing brightness, defect suppression, and device implementation. Finally, the challenges and future opportunities for realizing high color purity and efficient electroluminescent devices are discussed for the proposed next-generation display and lighting technologies.