Light Management in Tandem Cells by an Intermediate Reflector Layer

Recently, it was demonstrated that the insertion of TCO layers between the compound cells of tandem cells allows a shift of current generation from the bottom to the top cell [1]. This concept is particularly useful to increase the performance of a-Si:H/μc-Si:H tandem cells. In this paper we analyse experimental and optical modelling results of very different tandem cell structures in order to asses the full potential of the intermediate reflector concept. Whereas the wavelength response of the reflector is found to be well explained by coherent reflection at the TCO layer, the magnitude of current generation is found to be a strong function of texturing effects.