High-efficiency perovskite/silicon heterojunction tandem solar cells

Silicon solar cells reached record efficiencies close to their practical efficiency limit. A promising approach to further increase performance at low cost lies in combining silicon and perovskite solar cells to form a tandem device. Here, we present high-efficiency perovskite/silicon heterojunction tandem cells. From 4-terminal measurements, a total steady-state efficiency of up to 24.4% was obtained using maximum power point tracking. For monolithic tandems, which have the potential for higher performance but are more challenging to fabricate, efficiencies of 19.2% and 21.2% were reached on cell sizes of 1.22 and 0.17 cm2, respectively. These efficiencies are steady during >300 s of maximum power point tracking.