Solar Energetics

New materials and technologies for solar energetics

Group leader: Maarja Grossberg, Department of Materials Science, Tallinn University of Technology

The research group (RG) headed by Dr. Maarja Grossberg_Kuusk (previously headed by Prof. Enn Mellikov) has many decades of experience in studies of materials for photovoltaic (PV) applications. The focus of the RGs research is on the studies of low cost absorbers for PV and on the development of alternative solar cell structures. Kesterite semiconductors Cu₂ZnSnSe₄ and Cu₂ZnSnS₄, binary IV-VI compounds like SnS and other semiconductor compounds that are composed of low cost, Earth abundant elements are currently being studied as promising absorber material candidates for the next generation solar cells [phys. stat. sol. A 205 (2008) 167-170]. Synthesis routes and chemistry, post-treatment schemes and doping conditions for unique semiconductor monograin powders are being developed. Monograin powder growth technology is the main method used by the RG for the growth of absorber crystals for solar cells. In addition, several thin film technologies such as pulsed laser deposition, physical vapour deposition and magnetron sputtering are being applied for the growth of thin films absorbers [J Mater Sci: Mater Electron 24 (2014) 4739-4744].

The research group is known for their unique monograin layer solar cell design, the corresponding technology that can be used for different semiconductor materials was developed by the members of the team [Invention priority No: DE19981028310]. This technology is being implemented by spin-off companies of TUT, crystalsol OÜ and crystalsol GmbH.

The research team has also extensive experience in the studies of optoelectronic, structural and chemical properties of semiconductor materials and solar cells by using various methods such as temperature dependent photoluminescence, Raman scattering and modulation spectroscopies, Scanning Electron Microscopy based techniques, capacitance spectroscopy methods, I-V (T) studies etc. The RG has published many leading papers on the recombination mechanisms and complicated structural properties of kesterite absorbers [Thin Solid Films 519 (2011) 7403-7406; Appl. Phys. Lett. 101 (2012) 102102] as well as chemical etching regimes [Applied Surface Science 357 (2015) 795−798, Energy Procedia 10 (2011) 197 – 202].