Dr Simon Kirner
PVcomB,
Helmholtz-Zentrum Berlin, Germany
By : Dr Simon Kirner,
PVcomB, Helmholtz-Zentrum Berlin, Germany
(Invited Talk)
The tremendous increase in photovoltaic installations worldwide in the past decade proves that this technology can provide a great amount of clean and affordable energy to the global demand. However, it has the inherent drawback that its supply is subject to the cycles of nature (day-night, summer-winter), which makes it difficult to integrate into electricity systems on the large scale. The combination of solar with electrolysis to store the energy of light directly into hydrogen is therefore an imperative field of study, which currently attracts great interest in the scientific community.
In our talk, we briefly discuss different approaches with varying levels of integration of PV and electrolysis: starting from locally decoupled systems with DC/DC converters and integrated systems to complete monolithic, wireless “artificial leaf” structures and PEC cells.
We then focus on the advantages of thin film device technology that we pursue at PVcomB, such as the possibility of integrated monolithic series connection for integrated devices. Furthermore, we point out the great advantage of thin film silicon multi junctions for these applications, which lies in the easy fabrication of devices with open-circuit voltages of >2.8 V. The main design criteria for thin film silicon multi junction solar cells are briefly reviewed and the status of thin film silicon as well as wafer based solar cells fabricated at PVcomB is presented.
Then, we elaborate on two approaches for the integration of such cells in water splitting devices: One based on the combination of an a-Si:H/a-Si:H/µc-Si:H triple junction cell with alternative MoOx based (dark) catalysts for artificial leaf structures with solar-to-hydrogen efficiencies (STH) of >5%. And the other based on BiVO4 metal oxide in combination with several different types of silicon solar cells for true photo electrochemical cells with the target STH >6.6%. Finally, we show approaches for integrated solar fuel devices with potentially STH >12% all based on silicon.
(Authors : Simon Kirner, Bernd Stannowski, Rutger Schlatmann).
Biography of Dr Simon Kirner
Dr. Simon Kirner studied industrial engineering at TU Berlin and Stevens Institute of Technology. He received his Ph. D. in electrical engineering in 2013 from the TU Berlin for his studies about wide band gap silicon alloys for thin film silicon solar cells, which he pursued at Helmholtz-Zentrum Berlin (HZB).
Currently, he is a senior scientist at PVcomB, a department of Helmholtz-Zentrum Berlin, focused on the development of new processes for photovoltaic and water splitting devices on large area. He works on new materials for silicon-based solar cells, specifically nanocrystalline silicon oxide and other silicon alloys, deposited by plasma enhanced chemical vapor deposition. Furthermore, he develops new processes for silicon-wafer-based and -thin-film-based hetero-junction- and multi-junction-solar cells. His work includes optical and electrical device simulations. His most recent activity is the development of photovoltaic cells tailored for photo electrochemical devices with high stable efficiencies and potentially low costs.