An Overview of Chalcogenide Thin Film Materials for Tandem Applications

Tandem solar cells consisting of two absorbers with different bandgaps have shown great potential breaking the Shockley–Queisser (S–Q) efficiency limit of a single junction solar cell. As they do not induce additional area-related balance-of-system costs, such high-efficiency tandem solar cells can enable a reduction of the levelized cost of energy. Their tuneable bandgap puts chalcogenide thin film materials at the forefront of tandem research. Their bandgap is determined by absorber composition and thus can be adjusted to a wanted value. This property, together with their well-known stability makes them very appealing for optimization of tandem solar cells. In addition, high-efficiency thin-film tandem technologies would be attractive for low-weight and flexible applications. In this chapter, established chalcogenide thin film materials promising for tandem approaches are summarized and discussed.