tandemPV: A Review of c-Si-Based Tandem Technology and What is Needed to Bring it into Production

In the last decade the field of PV has become extremely dynamic in terms of implementation of innovations within solar cell development and module production. Al-BSF devices are beginning to fade out as more-advanced and higher-efficiency solar cells and modules enter the PV market. It is believed that c-Si-based tandem solar cells will also be commercially available within three to five years (possibly sooner), as also confirmed in the ITRPV roadmap. This paper provides a concise overview of existing c-Si-based 2-, 3- and 4-terminal tandem technologies, summarizes the current development status, and sets out the future roadmap. In addition, a discussion is included of what will be required over the coming years to bring these promising technologies to market, enabling commercial efficiencies above 30%.