Integration of photonic conversion layers based on photoemissive nanostructured materials for improving sunlight harvesting ability of solar cells – NANOSOLARCELL

The aim of this project is to increase the conversion efficiency of conventional photovoltaic solar cells by incorporating photonic up conversion layers based on photoemissive nanostructure materials. Such photonic layers will allow to take advantage of the UV radiation contained in the solar spectrum (about 5-8% at the earth level). Indeed, current solar cells are sensitive to photons located in the lower region of the solar spectrum (visible light), while incident UV photons are unused in photovoltaic processes. Upon incorporation of the photonic conversion layer to the electrodes of common photovoltaic devices (e.g., Si-based, perovskites, dye sensitized) we expect and overall conversion efficiency increase between 2-3%, due to a better exploitation of the solar spectrum.
Our approach consists in the incorporation of photonic conversion layers based on photoemissive carbon nanostructures and polymer complexes that are capable of harnessing such UV fraction of sunlight and can be easily implemented on existing PV cells. Hence, a cost-effective approach with minimal impact over the readily available fabrication techniques is proposed. Although the use of photonic up-converting materials has been already explored in the literature, the novelty of this proposal stands from the nature of the photonic layers, combining carbon nanostructures and polymers as well as the integration in electrodes of large dimensions to evaluate the performance of the full solar cells operating in real conditions (illumination and outdoor harsh environments), as opposed to common studies with the focus limited to measuring the indoor photochemical response of lab-scale electrodes. In this regard, previous studies of the consortium partners have demonstrated the photochemical characteristics of carbon nanostructures and polymer complexes with high photoemissive features, and that can be embedded in polymeric matrices to generate optically transparent polymer composite. Such materials can also be manufactured using low cost procedures and local resources (e.g., in the case of carbon nanostructures), which is extremely important for boosting their large scale implementation. Several photoemissive materials will be incorporated in different polymeric matrices to create the photonic layers, and cast them on commercial electrodes to determine the efficiency obtained by the systems. The aging mechanisms as a function of exposure to UV radiation, and as a function of the number of cycles of the temperature variation will be investigated in terms of the impact in the overall photovoltaic conversion. The materials will be tested for durability in aggressive environmental conditions (e.g., dust, high level of irradiation) in the African countries of the consortium.