Plasmonic-enhanced organic photovoltaics for wearable applications

The fast-growing field of smart textiles, with applications including wearable displays, biomedical devices and health-monitoring technology, demands energy. In this sense, textile based solar cells are becoming increasingly important, namely because they would enable energy harvesting to power other wearable electronic devices.[doi:10.3390/nano5031493].

The use of organic active materials in what is called organic photovoltaics (OPVs) is a very promising route to overcome many challenges posed by device integration into textiles, since these materials are flexible, lightweight, large-area and cost-effective. However, the commercialisation of OPVs requires improvements in terms of their efficiency, and although several strategies have resulted in breaking the 10% power conversion energy threshold, there is still a lot to be done. The main limitations of OPVs are related to the low carrier mobility and small exciton diffusion lengths, inherent to the organic active materials used, which in turn limits their film thickness, and this results in insufficient photon absorption and carrier generation.

The aim of this project is to realize highly efficient OPVs integrated on textiles. In order to overcome the limitations related to organic materials, the light absorption in OPVs will be increased by using plasmonic metamaterials. This approach was shown to extend the light absorption region in OPVs and improve the efficiency of the above mentioned devices [doi:10.1002/advs.201600123].

Two approaches will be targeted for plasmonic enhancement of OPVs, making use of both localised and surface plasmon resonances: the use of nanoparticles and similar nanomaterials, and the use of nanopatterned gratings, respectively.
The achievement of efficient, cost-effective and broad spectrum OPV devices built directly on textile substates will enable solar energy harvesting using items as common as clothes and garments. Since other type of devices have already been demonstrated by us using graphene on textile fibres (e.g. electroluminescent devices, touch sensors, temperature sensors, stress and strain gauges, with several publications currently under preparation), energy harvesting built on the same textile platforms, using plasmonic-enhanced OPVs, would provide the necessary power for such devices in a seamless way.

This is a truly multidisciplinary project, which involves graphene and 2D materials for wearable applications, a hot-topic in materials science and device engineering, as well as the necessary background in terms of physical properties, micro and nanofabrication. In addition to this highly transferrable skils, the student will be expected to visit Centexbel and learn skills related to the textile industry. The cohort and community approach in the CDT will facilitate the interaction with fellow students working in related areas and regularly using similar computational tools and fabrication equipment. Furthermore, the CDT promotes science and dissemination contributions from its students, which will not only help to bring this research to its ultimate stakeholders, society, it will also allow the student to spread the results in international conferences. The targeted conferences will include those with a strong industrial participation, to reinforce the links between academia and industry and open up way for fruitful collaborations.