In two separate studies, researchers report novel methods that enable the fabrication of high-performance perovskite-silicon tandem solar cells with power conversion efficiencies exceeding 30%.
Combining perovskite and silicon solar cells into a tandem device could provide a promising path toward high-performance PVs. Here, in the two separate studies, researchers present different strategies for developing perovskite-silicon tandem solar cells with a PCE exceeding 30%. In one study, Xin Yu Chin from Ecole Polytechnique Fédérale de Lausanne (EPFL) and colleagues showed that the uniform deposition of the perovskite top cell on a silicon bottom cell featuring micrometric pyramids – the industry standard configuration – can facilitate high photocurrents in tandem solar cells.
Chin et al. demonstrated that using phosphonic acid additives during the processing sequence of the cells not only improved the perovskite crystallization process, but also helped to alleviate recombination losses. In a proof-of-concept, the authors fabricated a device with an active area of 1.17 square centimeters that achieved a certified PCE of 31.2%.
Taking a different approach, Silvia Mariotti from Helmholtz-Zentrum Berlin (HZB) and colleagues showed that using an ionic liquid – piperazinium iodide – improved band alignment and enhanced charge extraction at the interface of a trihalide perovskite and the electron-transport layer by creating a positive dipole. Using this modification, Mariotti et al. developed a perovskite-silicon tandem solar cell that demonstrated an impressive open circuit voltage of up to 2.0 volts and a certified PCE of up to 32.5%.