To perform water splitting for hydrogen production, a high voltage of >2.2V is required.

Tandem solar cells are composed of two solar cells, each absorbing a different range of the solar spectrum, connected in series. This structure can not only use the full range of the solar spectrum, but can also output a high open-circuit voltage (VOC).

We have designed all-perovskite tandem solar cells with a high VOC of 2.25V, which we expect to further utilize in all-perovskite based water splitting devices in the future.