Graphene and carbon quantum dots have extraordinary optical and electrical features because of their quantum confinement properties. This makes them attractive materials for applications in photovoltaic devices (PV). Their versatility has led to their being used as light harvesting materials or selective contacts, either for holes or electrons, in silicon quantum dot, polymer or dye-sensitized solar cells. In this review, we summarize the most common uses of both types of semiconducting materials and highlight the significant advances made in recent years due to the influence that synthetic materials have on final performance.

C-Dots are the only component of the electroactive layer in solution processed LEDs and the only source of the white light.

Conductive hydrogels are becoming one of the most important milestones for the development of new scaffolds, biosensors, supercapacitors, and green electronics within the field of biomedicine. In this work, we study the effect of different types of electroactive additives such as poly(3,4-ethylenedioxythiophene), tannic acid, and carbon quantum dots (CQDs), to form different poly(vinyl alcohol) (PVA)-based hydrogels with enhanced electrochemical properties. Different physicochemical tests are carried out to characterize the different PVA-based hybrid hydrogels and the rates of their degradation and loss of electroactivity throughout an eight-week biodegradation process. This work shows the individual and synergistic effects of the additives on various mechanical properties, including storage modulus and swelling ratio, and electrochemical properties of the PVA hydrogel. The additives have proven to enhance the electroactivity of the PVA-based hydrogels but as well their degradation. Finally, the use of the new hydrogel as a pressure sensor is also investigated. The study provides an insight on the potential use of CQDs, in synergy with other electroactivity enhancers, in the fabrication of novel hybrid conducting hydrogels in green electronics. Graphical Abstract