Perovskite-perovskite tandem photovoltaics with optimized band gaps

TLDR

Tandem perovskite cells can be fabricated by tuning a top layer to absorb short wavelengths and a lower layer to absorb longer wavelengths, but achieving an all‑perovskite design is hindered by the lack of a material that absorbs the red end of the spectrum. An infrared‑absorbing mixed tin‑lead perovskite delivers 14.8 % efficiency alone and 20.3 % in a four‑terminal tandem cell. Eperon et al., Science, this issue p.

Abstract

Tandem perovskite cells The ready processability of organic-inorganic perovskite materials for solar cells should enable the fabrication of tandem solar cells, in which the top layer is tuned to absorb shorter wavelengths and the lower layer to absorb the remaining longer-wavelength light. The difficulty in making an all-perovskite cell is finding a material that absorbs the red end of the spectrum. Eperon et al. developed an infrared-absorbing mixed tin-lead material that can deliver 14.8% efficiency on its own and 20.3% efficiency in a four-terminal tandem cell. Science , this issue p. 861