Space charge behaviour in Quantum Dot/Epoxy resin nanocomposites for HVDC applications

This work investigates the feasibility of semiconductive nanostructures, namely Quantum Dots (QDs), as additives in polymeric matrices to improve dielectric properties. The primary aim is to explore how QD incorporation influences space charge behavior in an epoxy resin, DER332. The research begins with an overview of high voltage direct current (HVDC) systems and the increasing relevance of nanodielectric materials in advanced insulation technology. Given the inherent properties of QDs, their role as additives in altering dielectric performance is of notable interest. This study aims to bridge the gap between the fundamental theoretical properties of QDs and their practical application within polymeric insulation materials. Two nanocomposites were fabricated with QD loadings of 0.04% and 0.1%, respectively. A comprehensive experimental campaign, comprising both chemical and electrical measurements, was conducted to assess the effectiveness of QD incorporation into the epoxy matrix. Characterization efforts were focused on analyzing space charge distribution, charge trapping behavior, and the electric field profile within the QD-enhanced samples, also focusing on the conductive and dielectric properties of the analyzed materials. Three main findings emerged from the study: Firstly, the addition of Carbon Quantum Dots creates charge carrier traps within the matrix, leading to modifications in space charge behavior and altering the electric field distribution. Second, a novel method to evaluate space charge dynamics was preliminarily validated through short-term current transient analysis, providing a new potential approach for studying dielectric materials. Finally the results suggest that QDs can potentially enhance the field grading capabilities of epoxy Resins. In conclusion, the significant impact on the dielectric properties of epoxy resin due to the incorporation of a minimal amount of Carbon Quantum Dots requires further investigation, as it has the potential to contribute to the development of innovative materials in the field of insulation engineering.