瑞典卡尔斯塔德大学招聘招聘太阳能电池材料方向博士后

Post-doc in Solar Cell Materials : Karlstad, Sweden

The main responsibility of the postdoctoral researcher is to participate in the research projects on siliconbased solar cells. The postdoc is expected to have experiences in crystalline silicon solar cell production and characterization and should be able to set up new experimental tools and production teechnology independently. Interest and ability to participate in the second research project, on organic solar cell materials, would be valuable. The postdoc is expected to take active part in writing publications and research applications.

Description

Research description Karlstad University just started a research activity in the field of industrial type solar cells. Today, crystalline silicon is the most successful material for solar cells with a market share of about 90 %. Within this field, our research and development focuses on new and advanced production technologies within the whole value chain from the production of silicon feedstock to the manufacture of modules. One focus of the project is the analysis of defects (dislocations, grain boundaries, precipitates, dissolved impurities) in crystalline silicon to find out how they influence the efficiency of the solar cells. This involves material produced by advanced crystallization techniques like mono-casting or high performance silicon. Furthermore, the influence of the solar cell process on the defects is evaluated and process developments are planned with our partner institutions. The electrical material characterization at Karlstad University is done for example with high resolution light beam induced current (LBIC) mapping and minority carrier lifetime topography. For the lifetime measurements, a chemical surface passivation has to be developed. We are also setting up an automatic optical microscope, where automatic image recognition techniques will be developed to measure densities of defects, for example dislocation etch pit densities. This requires also some computer programming skills. Single defects should be analyzed with our transmission electron microscope (TEM), where the sample preparation technique has to be extended to silicon. Through international collaborations, synchrotron based characterization methods will be used. Aside from silicon, other new materials for solar cells are interesting. During the startup time, further characterization experiments will be set up at our laboratories. Later, they will be complemented by technology to produce solar cells, e. g. for emitter diffusion. Samples will be prepared amongst others using our scribing and cutting Laser. We have a strong international network to most of the relevant solar cell research institutions world wide, which in addition gives us access to their technologies. In another project on solar cell materials, the growth and properties of thin organic molecular layers of interest for photovoltaic applications are studied. The project focuses on layers of small conjugated molecules, single layers as well as heterostructures, deposited by evaporation. Important topics are the electronic levels and transport properties: the bandgap, sub-bandgap states, energy level alignment at the organic/organic heterointerfaces and at the electrodes.