Recent progress and future prospects of perovskite tandem solar cells

Organic–inorganic metal halide perovskite solar cells represent the fastest advancing solar cell technology in terms of energy conversion efficiency improvement, as seen in the last decade. This has become a promising technology for next-generation, low-cost, high-efficiency photovoltaics including multi-junction tandem cell concepts. Double-junction tandem cells have much higher efficiency limits of 45%, beyond the Shockley–Queisser limits for a single-junction solar cell. In this review, recent progress with the perovskite tandem solar cells is highlighted, in particular, with 2-terminal perovskite–Si, perovskite–CIGS [where CIGS = Cu(In,Ga)(S,Se)2], perovskite–organic photovoltaic, perovskite–perovskite, and 3-junction-perovskite tandems. The opportunity and challenges of two-terminal monolithic perovskite tandems are discussed including a roadmap of strategies for further improving their efficiencies.