Job description

In this postdoc research project you will develop luminescent materials for building-integrated photovoltaic (BIPV) technology. You will make and study new types of strongly absorbing sulphide luminescent solar absorber materials, just a few hundred nm thick, that can convert the UV and visible part of the solar spectrum into infra-red luminescence. When applied as a coating to windows, these materials can enable a cost-effective electricity-generating PV-window following the principle of a Luminescent Solar Concentrator (LSC). An LSC harvests sunlight by absorbing, re-emitting, and subsequently guiding light, like in an optical fibre, to solar cells integrated in the window pane that convert the light into electrical power.

In this project you use reactive DC, RF or pulsed magnetron sputtering, the workhorse technology of the glass coating industry, to make the luminescent materials. Targeted materials are Yb³⁺-doped inorganic semiconducting sulphide materials, emitting in the infra-red spectral range, where silicon solar cells have high conversion efficiency.

To successfully develop new luminescent absorber materials, it is crucial that you gain a fundamental understanding of the physical processes underlying their luminescence mechanism. To give you an idea, one of the scientific challenges is to understand how generated electron-hole pairs can transfer their energy to the luminescence centres. The strongest possible absorptions in an inorganic material are so-called bandgap absorptions, in which an electron is excited from the valence band (VB) to the conduction band (CB), leaving behind a hole in the VB. Although there are many materials (hosts) with a small bandgap that absorb the entire visible part of the solar spectrum (black materials), very few show efficient luminescence of doping ions. Such host-to-doping-ion transfer is often described as a resonant process between (self-trapped) exciton emission and doping-ion absorption. The materials in this project are selected to have a small exciton binding energy, making exciton-mediated transfer inefficient. Instead, sequential transfer of first the electron and then the hole is the anticipated transfer process to the Yb³⁺ luminescence centres.

The fundamental insights are obtained first by time- and temperature-resolved optical and luminescence spectroscopy, combined with a variety of techniques to analyse the structure, (defect) composition and morphology of the films. Secondly, fundamental understanding involves data interpretation and model development using knowledge of solid-state physics, optics and quantum mechanics. Ideally, the obtained insights will be used to select other materials with improved properties during your project.

The Energy Materials group at Delft University of Technology has more than 30 years of experience in luminescent materials research and collaborates with a start-up company and the glass coating industry to facilitate a route to large-scale application of the coatings as windows. You will work in a team, led by your supervisor, alongside Phd’s, technicians, a start-up company and the glass coating industry.

Job requirements

You are a skilful experimentalist with perseverance and patience, motivated to make new materials. Please show in your application that you have:

• a PhD in physics, inorganic (physical) chemistry or a similar field
• experience with magnetron sputtering
• a proven interest in, and experience with, experimental (materials) research

Experience with any of the topics mentioned in the job description is beneficial but not mandatory.

TU Delft (Delft University of Technology)

Working at TU Delft means contributing to solutions that really make a difference.

For over 180 years, we have been training engineers who make an impact worldwide in companies, government bodies, or as entrepreneurs. Our alumni turn knowledge into concrete solutions for the challenges of today and tomorrow.

These challenges are changing rapidly. That is why we focus on themes such as energy, climate, digitalisation, artificial intelligence (AI), and smart mobility every day. Our education and research are directly aligned with what society needs now and in the future.

At TU Delft, our people make the difference. With their knowledge and curiosity, our staff provide a high-quality education and conduct pioneering research that extends beyond the campus. You will have the opportunity to take the initiative, work with others, and grow as a professional.

Working at TU Delft means join an international community of professionals and students. Together, we create knowledge, innovations, and solutions that help move the world forward.

Faculty Applied Sciences

With more than 1,100 employees, including 150 pioneering principal investigators, as well as a population of about 3,600 passionate students, the Faculty of Applied Sciences is an inspiring scientific ecosystem. Focusing on key enabling technologies, such as quantum- and nanotechnology, photonics, biotechnology, synthetic biology and materials for energy storage and conversion, our faculty aims to provide solutions to important problems of the 21st century. To that end, we educate innovative students in broad Bachelor's and specialist Master's programmes with a strong research component. Our scientists conduct ground-breaking fundamental and applied research in the fields of Life and Health Science & Technology, Nanoscience, Chemical Engineering, Radiation Science & Technology, and Engineering Physics. We are also training the next generation of high school teachers.

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