Bandgap Engineering of Lead-Free Double Perovskite Cs2 AgBiBr6 through Trivalent Metal Alloying.

Journal Article

The double perovskite family, A2 MI MIII X6 , is a promising route to overcome the lead toxicity issue confronting the current photovoltaic (PV) standout, CH3 NH3 PbI3 . 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 Cs2 AgBiBr6 as host, band-gap engineering through alloying of InIII /SbIII has been demonstrated in the current work. Cs2 Ag(Bi1-x Mx )Br6 (M=In, Sb) accommodates up to 75 % InIII with increased band gap, and up to 37.5 % SbIII with reduced band gap; that is, enabling ca. 0.41 eV band gap modulation through introduction of the two metals, with smallest value of 1.86 eV for Cs2 Ag(Bi0.625 Sb0.375 )Br6 . Band structure calculations indicate that opposite band gap shift directions associated with Sb/In substitution arise from different atomic configurations for these atoms. Associated photoluminescence and environmental stability of the three-metal systems are also assessed.

Full Text

Duke Authors

Cited Authors

  • Du, K-Z; Meng, W; Wang, X; Yan, Y; Mitzi, DB

Published Date

  • July 2017

Published In

Volume / Issue

  • 56 / 28

Start / End Page

  • 8158 - 8162

PubMed ID

  • 28523742

Electronic International Standard Serial Number (EISSN)

  • 1521-3773

International Standard Serial Number (ISSN)

  • 1433-7851

Digital Object Identifier (DOI)

  • 10.1002/anie.201703970

Language

  • eng