Bandgap Engineering of Lead‐Free Double Perovskite Cs 2 AgBiBr 6 through Trivalent Metal Alloying

Abstract The double perovskite family, A 2 M I M III X 6 , is a promising route to overcome the lead toxicity issue confronting the current photovoltaic (PV) standout, CH 3 NH 3 PbI 3 . Given the generally large indirect band gap within most known double perovskites, band‐gap engineering provides an important approach for targeting outstanding PV performance within this family. Using Cs 2 AgBiBr 6 as host, band‐gap engineering through alloying of In III /Sb III has been demonstrated in the current work. Cs 2 Ag(Bi 1− x M x )Br 6 (M=In, Sb) accommodates up to 75 % In III with increased band gap, and up to 37.5 % Sb III with reduced band gap; that is, enabling ca. 0.41 eV band gap modulation through introduction…

• NS
  National Science Foundation
• UD
  U.S. Department of Energy

  Awards: ECCS-1542015, DE-EE0006712
• OO
  Office of Energy Efficiency and Renewable Energy

  Award: DE-EE0006712
• SE
  Solar Energy Technologies Program

  Award: DE-EE0006712
• DO
  Division of Electrical, Communications and Cyber Systems

  Awards: ECCS-1542015, 1542015
• OO
  Office of Energy Efficiency