Workgroup Emerging solar cell technologies

The group ” Emerging solar cell technologies” focuses on the conceptual evaluation of new process and solar cell technologies from basic research to industrial application. The underlying goal is to support our industrial partners (material manufacturers, equipment manufacturers, cell manufacturers), in addition to further reducing the levelized costs of electricity by increasing the electricity yield and upgrading photovoltaics for special applications. Currently, we are striving in particular to support the reestablishment of PV production in Europe. Specific to the group is the expected time horizon until successful technologies are transferred to industrial use of about 3 to 5 years. Current research focuses include the industrialization of passivating contacts based on doped polycrystalline silicon layers deposited on a thin passivating interface oxide (POLO, poly-Si on oxide), the extension of Si technology to tandem solar cells, and the adaptation of solar cell technology to the special application of vehicle-integrated photovoltaics.

The activities of the group are distributed over the following research areas, which build on each other:

Basic research on Si-based solar cell concepts

• Increasing the efficiency potential by applying novel concepts such as photonic crystals for better light trapping
• Development of optically and electrically optimized interconnection between subcells of monolithic tandem solar cells based on poly-Si based tunneling or recombination junctions
• Deepening the understanding of the device physics of 3-terminal tandem solar cells
• Demonstration of the efficiency potential of Si solar cells and of Si-based tandem solar cells on laboratory scale (often together with national and international partners)

Development of industrial single processes and complete process sequences for Si-based solar cell technologies 

• Development and optimization of p-type silicon-based solar cells combining high efficiency potential with lean process flow and low material cost due to the combination of electron-collecting POLO and conventional alloyed Al contacts (“POLO BJ, POLO IBC”)
• Development of a pure Al-based metallization
• Further development of these cell structures as low-cost 2- or 3-terminal bottom cells in Si-based tandem solar cells
• Development of industrially relevant deposition technologies for perovskites, in particular based on gas transport-assisted PVD processes

Application of Si solar cells for vehicle-integrated photovoltaics

• Setup and test operation of a practical, electrically powered light commercial vehicle with integrated photovoltaics, analysis of the energy flow and achievable range extensions
• (in cooperation with the Institute for Electronic Materials and Devices, LUH): Analysis of the effects of transient partial shading during driving on the PV yield

Processing services in the areas mentioned above

Example: Evaluation of wafer material or single components to highest efficiency cell level