Band Gap Tuning via Lattice Contraction and Octahedral Tilting in Perovskite Materials for Photovoltaics

Tin and lead iodide perovskite semiconductors of the composition AMX3, where M is a metal and X is a halide, are leading candidates for high efficiency low cost tandem photovoltaics, in part because they have band gaps that can be tuned over a wide range by compositional substitution. We experimentally identify two competing mechanisms through which the A-site cation influences the band gap of 3D metal halide perovskites. Using a smaller A-site cation can distort the perovskite lattice in two distinct ways: by tilting the MX6 octahedra or by simply contracting the lattice isotropically. The former effect tends to raise the band gap, while the latter tends to decrease it. Lead iodide perovskites show an…

• NS
  National Science Foundation

  Awards: 1147470, DGE-1147470
• UD
  U.S. Department of Defense
• UD
  U.S. Department of Energy

  Awards: 76SF00515, DE-AC02, AC02-76SF00515, DE-AC02-
• FW
  Fonds Wetenschappelijk Onderzoek
• VR
  Vlaamse regering
• OO
  Office of Science

  Awards: AC02-76SF00515, DE-AC02-76SF00515, DE-AC02, 76SF00515
• OO
  Office of Naval Research

  Award: DE-AC02-76SF00515
• DO
  Division of Graduate Education

  Award: DGE-1147470
• BE
  Basic Energy Sciences

  Awards: DE-AC02, DE-AC02-76SF00515, 76SF00515, AC02-76SF00515
• HM
  H2020 Marie Skłodowska-Curie Actions

  Award: 659225
• SN
  SLAC National Accelerator Laboratory

  Awards: AC02-76SF00515, DE-AC02-76SF00515