Joint project: P3T – Perovskite-POLO-PERC tandem solar cells and modules

Subproject: Tandem integration of co-evaporated perovskite solar cells on textured POLO-PERC bottom solar cells

The P3T project aims to develop highly efficient, large-area perovskite silicon tandem solar cells as a drop-in upgrade for existing production lines based on the established PERC silicon solar cell technology and to integrate them into demonstrator modules. In P3T, ISFH replaces the front side contact of a PERC cell with a passivating contact scheme (polycrystalline silicon on oxide, POLO), which is the basis for internal series connection. The process flow for solar cell production is deliberately based on existing PERC technologies, so that the industrialization of tandem solar cells as a drop-in upgrade is possible. The POLO-based series connection ensures that the recombination of charge carriers from the silicon cell at the interface to the top solar cell is greatly reduced. For a good optical coupling into the bottom solar cell and to remain close to the industrial PERC solar cell the tandem solar cell is textured. Therefore, ISFH is developing a co-evaporation process for the deposition of the perovskite top solar cell, which allows a conformal and scalable deposition. For this purpose, material systems for absorbers, electron or hole conducting materials are selected, which have been qualified by the project partners in wet chemical processes. A further topic of the ISFH subproject is the further development of characterization methods for tandem solar cells with the aim of identifying loss mechanisms. In the course of this, an industry-oriented characterization facility will be evaluated and further developed.