The Hybrid Nanosystems group is looking for 2 PhD candidates for a project that aims to unravel the structure-property relationship in hybrid metal-semiconductor nanosystems on a level of individual particles. How does the 3D morphology influence the charge and energy transfer between the metal and the semiconductor components? Can we (locally) tune this interaction by external stimuli? Finding answers to these questions will pave the way towards achieving smart functionality and robustness for energy-harvesting and quantum-processing materials of the future.

Metal and semiconductor nanoparticles (NPs) are emerging as key materials for solar energy harvesting, photocatalysis and photonics. The distinct optical properties of metal NPs stem from the collective oscillation of electrons (plasmons) upon incoming electromagnetic radiation. This makes them strongly interact with visible and near-infrared light, resulting in intense local electromagnetic fields in the vicinity of plasmonic metal NPs. Semiconductor NPs such as quantum dots generate bound electron-hole pairs (excitons) upon absorption of light of an energy larger than the band gap. The latter is a function of size, shape and material and can be tuned from the UV to the infrared. The excited electron-hole pairs can either recombine resulting in photoluminescence, be harvested in photovoltaic applications or promote chemical reactions involving reduction-oxidation processes in photocatalysis.

When both NP types are brought in close vicinity, the charge carriers in the coupled system can interact with each other, potentially leading to charge and energy transfer. This exchange can be used to alter absorption and emission of light, and to enhance chemical reaction rates and photovoltaic efficiencies in such coupled systems. In this manner, existing properties can be enhanced and novel properties might emerge as a consequence of the interaction. The interplay between the different components is dictated by the exact morphology of the hybrid nanosystem, an effect that is masked by averaging over many NPs. To overcome this problem, the interaction between semiconductor and metal NPs needs to be studied on a single NP level by correlating structural and optical properties on the same nanosystem.

In this work, you will investigate the energy and charge transfer processes in hybrid nanosystems and measure the interaction between single metal, semiconductor and dielectric NPs. To reach that goal, you will build a single-particle scattering and (time-resolved) luminescence measurement setup. To correlate the optical properties of the NPs to their morphology, you will perform electron microscopy on the same nanoparticles. The challenge will be to determine not only the 2D but also the 3D arrangement of the coupled NPs. To this end, you will make use of electron tomography. The project will also include modifying the surface chemistry of NPs and applying external stimuli to alter the interaction in hybrid nanosystems. The end goal of the project is unravelling the physics of key interactions within the hybrid nanosystems and finding means for precisely controlling them.

We are looking for an outstanding and highly motivated physicist or chemist.  Prior experience in (single-particle) optical spectroscopy and microscopy as well as interest in numerical calculations and colloidal synthesis is preferred. You will need to meet the requirements for an MSc-degree, to ensure eligibility for a Dutch PhD examination.

The position is intended as full-time (40 hours / week, 12 months / year) appointment in the service of the Netherlands Foundation of Scientific Research Institutes (NWO-I) for the duration of four years, with a starting salary of gross € 2,441 per month and a range of employment benefits. After successful completion of the PhD research a PhD degree will be granted at a to be determined Dutch University. Several courses are offered, specially developed for PhD-students. AMOLF assists any new foreign PhD-student with housing and visa applications and compensates their transport costs and furnishing expenses.

Hybrid Nanosystems

You will perform this research in the Hybrid Nanosystems research group headed by Wiebke Albrecht at AMOLF. The Hybrid Nanosystems group combines single-particle optical and advanced electron microscopy to answer fundamental questions about the complex interaction between different classes of nanomaterials. We also explore new architectures for creating functional and smart hybrid nanosystems.

AMOLF performs leading research on the fundamental physics and design principles of natural and man-made complex matter, with research in 4 interconnected themes: nanophotonics, nanophotovoltaics, designer matter, and biophysics. AMOLF leverages these insights to create novel functional materials, and to find solutions to societal challenges in renewable energy, green ICT, and health care. AMOLF is one of the NWO-I national research institutes located at the Amsterdam Science Park, Amsterdam, The Netherlands. It has approximately 130 scientists and a total size of ca. 200 employees. Furthermore, it hosts the Amsterdam NanolabNL clean room, which is part of the national NanoLabNL cleanroom network. See also www.amolf.nl