Ph.D. Student to work on Wearable Luminescent Solar Concentrators

Empa is the research institute for materials science and technology of the ETH Domain and conducts cutting-edge research for the benefit of industry and the well-being of society.

Ph.D. Student to work on Wearable Luminescent Solar Concentrators

In our research group, we study the interaction between optically active molecules and polymers and control their nanoscale arrangement. This is achieved by polymer synthesis (hydrogels, amphiphilic polymers, and nanocomposites) and their functionalization with chromophores and fluorophores. We target the design of smart materials for optical sensors, light-controlled drug delivery systems, and solar energy harvesting devices.

Project Background: One method to ameliorate the disadvantages of flexible solar cells (FSC) is the use of luminescent solar concentrators (LSC). Such materials absorb sunlight and convert it to the wavelength that is optimal for the SC, creating a geometric and spectral concentration of the light. In addition, LSC work under diffuse or artificial light or partial shading. Although rigid LSCs have been investigated for building-integrated SCs for 30 years, research into textile-based, flexible, and portable LSCs is at the beginning.

Our group has been developing fiber- or membrane-based LSCs that can be integrated with FSC. We employed amphiphilic polymer co-networks (APCNs). We incorporated hydrophilic and hydrophobic dyes in the corresponding domains and used the high interfacial area and close domain-domain distances to induce high energy transfer between dyes that are otherwise immiscible. FRET efficiencies of up to 60 % were observed, with a total energy transfer efficiency of about 99 %. The material was attached to wearable solar cells, helping to increase the power conversion efficiency of dye-sensitized solar cells by up to 84 %.

Project description: In this project, we will continue the research described above. It will contain both a scientific and an applied research component. We want to further investigate the energy transfer among fluorophores in APCNs, including the use of quantum dots and perovskites. We will study the effect of APCN formulation and morphology on its mechanical, adhesive, and optical properties, and how it steers the energy transfer. The project will also be dedicated to investigating demonstrators of wearable LSCs, by integrating the best-developed materials with flexible solar cells.

The candidate should have a strong background in Materials Science or Chemistry. We are looking for a highly motivated person capable of working in a multidisciplinary environment, driven by scientific curiosity, and open to learning new topics. The Ph.D. candidate needs to be proficient in spoken and written English and have a Master's degree. S/he will participate in writing scientific publications and presenting data at national and international scientific conferences. Previous experience in one or more of the following topics is required: LSCs, polymer networks, aluminosilicate nanoparticles, fluorescence lifetime, FRET.

The work will be carried out at Empa St. Gallen under the supervision of Dr. Luciano F. Boesel. The PhD student will be affiliated at ETH Zürich (Prof. René Rossi).