Advanced Nanomaterials for Solar Energy Conversion

The efficient use of solar energy for the generation of clean energy by using excitonic solar cells, is an attractive and prominent route to partially address the current worldwide energy crisis and climate issues. 

Excitonic solar cells are low-cost, light weight and largely scalable devices, which belong to an appealing class of the third-generation photovoltaics. This type of solar cells can be utilized to exploit a large region of the solar spectrum, including diffused visible light up and the near infrared (NIR) range, which are typically lost in the commercial Si-solar cell technologies. However, more efforts towards achieving and pushing the current record of photoconversion efficiency and long-term stability of excitonic solar cells, in particular in dye-and quantum dot sensitized solar cells (DSSCs and QDSCs) are required. Similar configurations of the photoactive part of the QDSCs, i.e. photoanode, can be employed to produce fuel within photoelectrochemical cells. A careful design of nanomaterials can play a critical role in the physical-chemical processes governing the device mechanisms such as exciton generation, separation, charge injection and transport. Consequently, understanding of these mechanisms are key to fabricate high performance devices for solar energy conversion into electricity or hydrogen. 

Our interdisciplinary research is focused on developing advanced engineered nanomaterials with novel device architectures, which can enhance the overall photoconversion efficiency as well as the long-term stability of DSSCs, QDSCs and QD-based photoelectrochemical cells. These nanomaterials include: hierarchical structures, nanowires, nanorods and composites of carbonaceous materials with wide band gap semiconductors as charge transporting scaffolds; colloidal core/shell QDs with different core size/shell thickness and dye molecules as light harvesters, and one-dimensional nanohybrid architectures within counter-electrodes. The complete characterization of the physical and electrochemical processes related to charge photo-generation, transport and collection, are investigated through state-of-the-art experimental techniques, correlating the interfacial properties of the composite materials and the prototype devices.