The next 'big' thing in photovoltaics
Mastering the properties of excitons offers the ability to guide energy at the nanoscale. Specifically, excitons have no net charge and can be split or combined. Researchers sought to use this flexibility to generate multiple carriers in quantum dot-sensitised solar cells (QDSSCs) at an efficiency exceeding that of conventional silicon solar cells. Being an analogue to dye-sensitised solar cells, QDSSCs are subsumed under the category of excitonic solar cells. The EU-funded project F-LIGHT (Förster resonant energy transfer for high efficiency quantum dot solar cells) was devoted to demonstrating that suitably tailored light harvesters can boost their energy conversion efficiency by regulating exciton dynamics. The F-LIGHT team added donor-acceptor pairs composed of commercially available dye molecules and colloidal and non-colloidal quantum dots. The aim was to exploit the Förster resonant energy transfer process. The donor component can absorb high-energy photons and efficiently transfer the energy to the anchored primary absorber (acceptor). Researchers synthesised new composite nanomaterials that increase charge collection and inhibit charge recombination in the oxide-based photoanode of excitonic solar cells. In addition, they have developed composite quantum dots and thoroughly investigated their optical properties before and after grafting with the oxide. F-LIGHT research into the processing of nanostructured oxides and quantum dots offered valuable insights into the physical phenomena occurring in QDSSCs. Project results lay the groundwork for the practical realisation of third-generation QDSSCs, promising to overcome the low energy conversion efficiency of excitonic solar cells.
Keywords
Photovoltaics, exciton harvesting, energy conversion, quantum dot-sensitised solar cells, F-LIGHT
