1. 2 New Materials and Concepts for Cells and Modules
Summary / Abstract:
We present a detailed analysis of the electrical losses derived from the standard P1-patterning line in comparison to working modules with post-absorber P1-patterning and subsequent P1-filling by either inkjet or photolithography printing. We utilize in-situ electro- and photo- luminescence high resolution imaging of full modules to rationalize their electrical performance. We further consider the close-to-real operating conditions by applying a forward bias potential in the vicinity of the maximum power point followed by a light soaking pre-conditioning step to avoid transient behaviours. In this way, we can accurately pinpoint power-loss channels on finished modules with various compositions and patterning strategies. 22.2% and 22.8% Cu content as well as modules with P1-filling through inkjet printing and photolithography were utilized. The necessary patterning architectures for the realization of the filling of the P1 line with a dielectric ink for the electrical isolation of the adjacent sub-cells creates a half-cell (i.e. cell with missing top or bottom contact), which introduces new parasitical loss sources. We further validate our findings with industrially produced, large size (1.2 m x 0.6 m) modules fabricated with post-absorber P1-patterning and subsequent P1-filling through photolithography printing. To overcome, or minimize this loss it is necessary to reduce the extent of the half-cell to an absolute minimum. This might be possible with the state-of-the-art machine accuracy and printing resolution. However, this additional loss has to be kept in mind when talking about the potential efficiency gain and advantages of P1-filling architectures. In light of these results, we established a measurement protocol for the accurate electrical evaluation of future innovative module interconnection schemes. We envision this analysis protocol to be of critical importance when developing different cellarchitectures, such as perovskite/CIGS tandems.
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