Narrow Results

Graphene quantum dots (GQDs) have been extensively studied in recent days due to their excellent optical photo-absorption, low-cost synthesis and nontoxic nature. Furthermore, the optical and electronic properties of GQDs can be modulated by adding various dopant (like N, S, B, F, K, Si etc.) and can be used as a potential candidate for green solar energy material. Here, we have synthesized GQDs, N and N, S co-doped GQDs using low-cost hydrothermal process. Quantum dot sensitized solar cells (QDSSCs) were fabricated by sensitizing doped and undoped GQDs with ZnO nanorods. Current-Voltage characteristics of GQD sensitized ZnO NRs, N-GQD sensitized ZnO NRs and S, N-GQD sensitized ZnO NRs have been studied. The superior photovoltaic performance was obtained using S, N co-doped GQDs sensitized ZnO NRs with conversion efficiency $\sim 0.131$%, which was 1.75 times higher than undoped GQD sensitized QDSSC device.

Graphene quantum dot (GQD), a zero-dimensional material with size less than 10 nm, is a newly developed member of the graphene family. GQDs have become highly promising materials in various applications, including catalysis, bioimaging, energy conversion, and storage, owing to their unique physicochemical properties, such as excellent photoluminescence, biocompatibility, low toxicity, easy fabrication, and edge effect. Additionally, oxygen-containing functional groups such as −COOH, −COC-, −OH, −CHO, and −OCH₃ play a crucial role in the structure of GQD_s. Oxygen is located in different edges and the basal plane of GQD_s. The unique architecture of oxygen inside the structure of GQDs and the outstanding properties and performance of GQDs provide a powerful impetus to use GQD_s as a promising material with applicability in various fields. In this chapter, we describe the possible structure, application, and critical role of the oxygen-containing functional group on the essential properties and application of GQD_s. Finally, we provide a brief outlook to point out the issues that need to settle for further development.