Relaxed Current Matching Requirements in Highly Luminescent Perovskite Tandem Solar Cells and Their Fundamental Efficiency Limits

Alan Bowman, Felix Lang, Yu-Hsien Chiang, Alberto Jimenez-Solano, Kyle Frohna, Giles Eperon, Edoardo Ruggeri, Mojtaba Abdi-Jalebi, Miguel Anaya, Bettina Lotsch, Samuel Stranks

Research output: Contribution to journalArticlepeer-review

38 Scopus Citations

Abstract

Perovskite-based tandem solar cells are of increasing interest as they approach commercialization. Here we use experimental parameters from optical spectroscopy measurements to calculate the limiting efficiency of perovskite–silicon and all-perovskite two-terminal tandems, employing currently available bandgap materials, as 42.0% and 40.8%, respectively. We show luminescence coupling between subcells (the optical transfer of photons from the high-bandgap to low-bandgap subcell) relaxes current matching when the high-bandgap subcell is a luminescent perovskite. We calculate that luminescence coupling becomes important at charge trapping rates (=106 s–1) already being achieved in relevant halide perovskites. Luminescence coupling increases flexibility in subcell thicknesses and tolerance to different spectral conditions. For maximal benefit, the high-bandgap subcell should have the higher short-circuit current under average spectral conditions. This can be achieved by reducing the bandgap of the high-bandgap subcell, allowing wider, unstable bandgap compositions to be avoided. Lastly, we visualize luminescence coupling in an all-perovskite tandem through cross-section luminescence imaging.
Original languageAmerican English
Pages (from-to)612-620
Number of pages9
JournalACS Energy Letters
Volume6
Issue number2
DOIs
StatePublished - 2021

NREL Publication Number

  • NREL/JA-5900-79254

Keywords

  • charge trapping
  • efficiency
  • energy gap
  • light
  • luminescence
  • perovskite

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