Phd Position Developing Luminescent Nanocrystal Layers to Enhance Biomass Production in Algal Cultivation

The use of non-renewable resources is causing global-scale environmental problems, which threaten the stability of our planet earth. The safe operating space to maintain liveable conditions on earth has been formulated in the planetary boundaries, of which several are already overstepped. Many of these problems are caused by human interruptions of biogeochemical cycles of the biogenic elements carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur leading to the creation of waste.

Zero Waste is a part of the university-wide theme of Sustainable Prosperity presented in the University of Amsterdam’s (UvA) 2021-2026 strategic plan. With Zero Waste, the UvA Faculty of Science (FNWI) aims to contribute to alleviating these environmental problems resulting from the current linear use of resources by (re-)designing processes, materials, and products to keep materials in closed cycles while meeting our needs.

Zero Waste will strongly connect to education at the Faculty of Science, especially to the new BSc programme Science and Design that focusses on four interdisciplinary themes: 1) high-tech designer materials, 2) renewable energy and resources, 3) engineering life and health, and 4) information science, modelling and simulation. Six Science & Design Doctorates will form the start of the Zero Waste research theme. They will work together in physical proximity and intensive interaction to strengthen the common aspects of the projects, while researching a broad range of topics. Physically, research and demonstration activities and part of the research of the theme can be carried out in SustainaLab , the new Matrix ONE building at Amsterdam Science Park .

Aim of the PhD project is to develop spectral shaping layers based on fluorescent nanocrystals and nanophotonics to enhance biomass production in algal cultivation. Recent breakthroughs allow the synthesis of fluorescent semiconductor nanocrystals with near-unity quantum yield, offering great opportunities as spectral shapers to optimize the solar spectrum to the needs of agricultural crops and algae. At the same time, substantial knowledge is available on the effect of (artificial) lighting on the growth of algae. In this project, we combine both worlds and develop light-shaping nanocrystal foils to investigate their potential for algal yield enhancement. The research will be carried out in an inspiring interdisciplinary collaboration, in the nanocrystal and optics labs of Prof. P. Schall  at IoP, and the algae incubator labs of Prof. J. Huisman  at IBED.

What are you going to do

Fluorescent semiconductor nanocrystals have great potential to be used in sustainable energy applications such as new-generation photovoltaic devices and spectral shapers. The latter offer great opportunities to directly convert the sunlight to boost PV efficiency or enhance photosynthesis to foster plant growth and increase biomass.

In this project, we apply highly luminescent nanocrystal layers to boost the growth of algae as sustainable biomass. Algae are developing to be an important source of sustainable feedstock as well as fish- and livestock feed, and growing them cost-effectively and sustainably with natural light is crucial for the green economy transition. Yet, algae use only limited portions of the available solar spectrum (the “photosynthetically active radiation” or PAR that spans the 400-700 nm region). Moreover, the pigments of different algal species (e.g., green, red and brown algae) absorb different wavebands within the PAR range. The solar spectrum, however, is much broader, spanning from the UV to the near infrared, thus containing much more energy than the PAR alone.

Taking advantage of recent developments in nanoscience, the PhD candidate will create optically active foils that convert light outside the PAR into the desired regions of the PAR that are most useful for algal growth. This will enhance their yield under natural light conditions. More specifically, we envision to convert harmful UV into blue, green or red light useful for plants and algae thereby maximizing the yield per hectare. The nanocrystals used in the initiative are ideally suited as spectral converters, having strong colour tunability, superior optical properties and are expected to be easily embedded into plastic or glass layers at the desired concentration, thereby allowing industrial application of the technology in algal bioreactors and greenhouses.

The PhD candidate will synthesize the nanomaterials, make efficient light-converting foils with added photonic design for light-outcoupling, and characterize the spectral properties of the foils. Furthermore, he will measure the photosynthetic rates and yields of different algal species at different wavelengths. The spectral characteristics of the foils and photosynthetic characteristics of the algae will be combined in mathematical models and experiments to assess the growth enhancement by the foils. These results will be used to optimize the foils for maximal yields of algal species with different photosynthetic pigments.

The position will be embedded in an inspiring interdisciplinary research environment of the Institute of Physics and the Institute for Biodiversity and Ecosystem Dynamics. The project is further embedded in a collaboration with users: commercial algae growers, as well as flow chemistry and foil producing companies to scale up the technology, and test it in commercial algae production. This integration of science and application should lead to knowledge utilization and commercial impact on the time scale of the PhD.