dr. Sven Askes, MSc

Assistant Professor, Faculty of Science, Biophysics Photosynthesis/Energy

Assistant Professor, Faculty of Science, Photo Conversion Materials

Assistant Professor, LaserLaB, LaserLaB - Energy

Personal information

My background includes 10 years of academic research experience, at the crossroads of photophysics, nanophotonics, materials science, (bio)inorganic chemistry, heterogeneous catalysis, and nanotechnology. Highlights include the successful development of: (i) molecular photon upconversion in nanoscale drug carriers for light-activated anticancer therapy (PhD, Leiden), (ii) light-driven CO-releasing molecules and materials for medical applications, based on molecular photochemistry and triplet-energy transfer mechanisms (PD1, Jena), (iii) photoelectrochemical synthesis of catalytic plasmonic nanostructures (PD2, AMOLF), (iv) alternative plasmonic materials and nanostructures for plasmonic photochemistry and nanoscale heating (VENI PD, AMOLF & VU). I am currently leading an ambitious research program on plasmonic photothermal catalysis within the PhotoConversion Materials group, funded by VENI & NWO-XS grants.

My vision for the next 10 years is to (i) make meaningful contributions to the understanding of how we can leverage material, nanostructure, time dynamics, nanoscale energy flow, and heterogeneous interfacial processes for light-energy conversion technologies, and to (ii) apply this knowledge in the development of useful nanophotonic, material science, and photochemical technologies.

Research

Heating of heterogeneous catalytic processes in industry still relies on burning fossil fuels to heat the entire reactor. It would be more energy efficient and sustainable to only apply heat where the chemistry occurs: at the surface of the catalyst. This has become possible with light and plasmonic nanostructures, which together afford wireless and remote spatiotemporal control over heat generation with nanoscale precision. Despite decades of research, photon-to-product efficiencies in state-of-the-art photothermal catalysis are still irrelevant for chemical industry, because the way plasmonic nanotechnology is used as heat source in lab-scale catalysis is fundamentally inefficient.

The current challenges are: (i) under CW light illumination the sub-wavelength heat-localization at the nanoparticles is lost and indiscriminatory heating of the whole reactor occurs, (ii) high light-scatter causes unpredictable heat gradients inside the catalyst solid, making chemistry hard to control, (iii) the use of structurally fragile and unstable plasmonic materials (e.g. Au, Ag) prevents reliable and robust operation. To summarize: the thermal management, nanophotonic aspects, and material robustness of photothermal catalysis remains unaddressed.

The overarching goal of my research is to revise the nanophotonic design and nanoscale heat management of photothermal chemistry in time and space in order to (1) make every photon count and obtain industrially-relevant photon-to-product yields, (2) steer chemical reaction pathways through dynamic chemical kinetics, and (3) achieve operational stability and robustness. I will reach this main goal by separately revising the four fundamental aspects of photothermal catalysis and define four key objectives. These objectives target (i) the heat and time management of chemical kinetics, (ii) the internal thermal management of the nanoreactor, (iii) the external thermal management of the nanoreactor, (iv) the light absorption and material stability.

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