Recent progress of carbon-quantum-dot-based photodetectors

Abstract

Photodetectors are essential electronic components of modern systems, allowing applications in wearable electronics, optical communication, environmental monitoring, biomedical diagnostics, and imaging. The scalability, versatility, and cost-effectiveness of conventional photodetector materials, such as silicon, III–V semiconductors, and metal oxides, are generally limited by the need for high-temperature and vacuum-based production techniques. Carbon quantum dots are quasi-zero-dimensional carbon nanomaterials, typically smaller than 10 nm, with tunable electronic and optical properties arising from quantum confinement, defect states, and surface functional groups. Their low toxicity, solution processability, broadband light absorption, and compatibility with flexible substrates make them promising materials for next-generation photodetectors. Recent developments in CQD-based photodetectors are summarised in this overview, with a focus on design strategies that have been published in the last few years. Bandgap engineering, charge transport mechanisms, interface engineering, and optical absorption are among the basic electronic and optoelectronic characteristics of CQDs that are examined from both theoretical and experimental viewpoints. The importance of theoretical modeling in comprehending carrier dynamics and maximizing device performance is emphasized. Key performance investigations, including responsivity, detectivity, response speed, and external quantum efficiency, are discussed with the recent advancements of device designs. Future research directions aiming at achieving self-powered, low-cost, and commercially viable CQD-based photodetectors for next-generation optoelectronic applications are also discussed, along with the issues related to material stability, reproducibility, interface defects, and large-scale manufacturing.