Objective

In this project we will increase the efficiency of thin-film silicon solar cells on flexible substrates by solving the issues linked to material quality, interface properties and light management, thus enabling lower production costs per Watt-peak. The general technological objectives of the project are the development of better materials and enhanced interfaces for thin film silicon solar cells, and to transfer the developed processes to an industrial production line.

The most important project goals are:

• Reduction of optical reflection and parasitic absorption losses: Design and industrial implementation of textured back contacts in flexible thin film silicon solar cells.
• Reduction of recombination losses: Development and implementation of improved silicon absorber material.
• Reduction of electric losses: Graded TCO layers which minimize the work function barrier between the p-layer and the TCO layer without loss of conductivity and transmission of the TCO.

In addition, the top layer of the TCO stack should provide a good protection against moisture ingression. In order to achieve these objectives more in-depth knowledge is needed for several relevant key areas for thin film silicon solar cells.

The main scientific objectives are:

• Identification of the ideal texture for the back contact. This structure should maximize the light trapping in thin film silicon solar cells without deterioration of open-circuit voltage and fill factor.
• Paradigm shift for the growth of microcrystalline silicon . In this project we want to show that it is possible to use microcrystalline silicon with high crystalline fractions leading to better current collection without voltage losses, and without crack formation when grown on nano-textured substrates.
• Deeper understanding of moisture degradation mechanisms of common TCO s like ITO and AZO.