High efficiency perovskite/heterojunction crystalline silicon tandem solar cells: towards industrial-sized cell and module

29.2%-conversion efficiency of a two-terminal (2T) perovskite/crystalline Si heterojunction tandem solar cell using 145 mu m thick industrial Czochralski (CZ) Si wafer is obtained. The structural optimization, such as surface passivation of the perovskite layer and better light management techniques, improved power conversion efficiency (PCE). To our knowledge, this PCE is the best in 2T-tandem solar cells using CZ wafers. Towards industrialization, crucial issues with the 2T tandem solar cells with crystalline Si bottom cell are discussed. Four-terminal (4T) tandem solar cells are evaluated as an approach to avoid the crucial issues. Examining our base technologies which realize 22.2%-conversion efficiency perovskite single junction solar cell module and 26%-heterojunction back-contact solar cells, we clarified that the based technologies were ready to realize 30%-conversion efficiency 4T perovskite/heterojunction crystalline Si tandem solar cells with approximately quarter size of an industrial crystalline Si solar cell (similar to 64 cm(2)).