DIFFER (Dutch Institute for Fundamental Energy Research) is one of the Netherlands Organisation for Scientific Research (NWO) institutes and focuses on a multidisciplinary approach to energy research, combining physics, chemistry, engineering and materials science. The institute is based on two main strands, solar fuels for the conversion and storage of renewable energy and fusion-energy as clean and unlimited source of energy. DIFFER is developing and supporting a national network on fundamental energy research and is closely collaborating with academic institutions, research institutes and industry. As of 2015 the institute is located in a new building at the campus of Eindhoven University of Technology (TU/e).
The present vacancy is for a shared Postdoc position between the Nanoscale Solar Cells group of prof. Erik Garnett at AMOLF (Amsterdam) and the Nanomaterials for Energy Applications group of dr. Andrea Baldi at DIFFER (Eindhoven).
One of the most significant recent developments in the field of photocatalysis is the use of light-driven plasmon resonances to optically tune the activity of heterogeneous catalysts. Plasmon resonances can activate specific catalytic pathways via two different non-thermal mechanisms:
1. Generation and injection of hot charge carriers into molecular adsorbates, or indirect mechanism.
2. Promotion of an electron from the metal to an empty molecular orbital of the adsorbate, or direct mechanism.
The indirect mechanism suffers from low quantum efficiency due to ultrafast relaxation of the hot charge carriers and can therefore only promote charge transfer to electronic states close to the metal Fermi energy. On the contrary, and crucially from a catalysis perspective, the direct mechanism bypasses electron-electron scattering and has the promise of reaching much higher and technologically relevant efficiencies. Distinguishing between the indirect and direct mechanisms is however very challenging and we still miss a conclusive experimental demonstration of the direct transfer from a plasmonically excited particle to an empty molecular orbital at its surface. Such lack of clear experimental evidence has undermined any attempt at elucidating the physical mechanism of direct charge transfer and therefore at exploiting it for potential applications.
The present research project tackles this fundamental question and aims at demonstrating experimentally the nature of plasmon-induced electron transfer in catalytic reactions. The key ingredient will be the rational tuning of the plasmon resonance of the metal nanoparticles with respect to the molecular electronic states at their surface. The electron transfer process will be studied by measuring the linewidth broadening of the plasmon resonance in individual nanoparticles as well as the spectroscopic signature of chemical products, using single-particle techniques such as dark-field scattering spectroscopy (DIFFER), surface enhanced Raman spectroscopy (DIFFER), single particle absorption spectroscopy (AMOLF), and cathodoluminescence spectroscopy (AMOLF).
About the group
The proposed project is a collaboration between the Nanomaterials for Energy Applications group of dr. Andrea Baldi and the Nanoscale Solar Cells group of prof. dr. Erik Garnett. As such, part of your responsibility will be to coordinate the joint experimental efforts between the two groups. The research tasks are highly interdisciplinary, ranging from nanophotonics modeling, to optical microscopy and spectroscopy, to the characterisation of catalytic reactions in flow cells. In particular, you will:
• Design optimal particle/adsorbate couples to study plasmon-driven electron transfer processes.
• Synthesise the desired plasmonic nanoastructures, either colloidally or via lithographic methods.
• Characterise the plasmon resonance linewidth in presence and absence of the molecular adsorbate, using single particle spectroscopy techniques.
• Assist in the coordination and supervision of PhD, master, and bachelor students.
• Write scientific publications and present your work at national and international conferences.
We seek an outstanding candidate that is willing to work in an international and interdisciplinary team of chemists and physicists. You should have a recent PhD degree in chemistry, physics, materials science or a closely related field. Prior experience in nanoparticle synthesis or optical microscopy and spectroscopy is not required, but is considered a plus. You should be willing to split your working schedule between DIFFER (Eindhoven) and AMOLF (Amsterdam), which will necessarily involve some commuting time (see www.ns.nl for scheduling and commuting times). Of course, we expect you to have excellent verbal and written communication skills in English.
Terms of employment
DIFFER and AMOLF are two of the nine research institutes of the Netherlands Organisation for Scientific Research (NWO). In our institutes we focus on multidisciplinary approaches to energy research, combining physics, chemistry, and materials science. You will have a temporary employment contract for the duration of 1 year with the intention for an extension of another year. The postdoc position is a scale 10 position (Collective Labour Agreement for Research Centers). The gross monthly salary is dependent on qualifications and experience and will be up to a maximum of €4,154 per month. The salary is supplemented with a holiday allowance of 8% and an end-of year bonus of 8.33%. NWO has a number of regulations that support employees in finding a good work-life balance. Such as conditions for teleworking, partly paid parental leave and the possibility to purchase and sell holiday leave. General information on working at NWO can also be found here.