Tuning the Structural and Optoelectronic Properties of Cs 2 AgBiBr 6 Double‐Perovskite Single Crystals through Alkali‐Metal Substitution

Abstract Lead‐free double perovskites have great potential as stable and nontoxic optoelectronic materials. Recently, Cs 2 AgBiBr 6 has emerged as a promising material, with suboptimal photon‐to‐charge carrier conversion efficiency, yet well suited for high‐energy photon‐detection applications. Here, the optoelectronic and structural properties of pure Cs 2 AgBiBr 6 and alkali‐metal‐substituted (Cs 1− x Y x ) 2 AgBiBr 6 (Y: Rb + , K + , Na + ; x = 0.02) single crystals are investigated. Strikingly, alkali‐substitution entails a tunability to the material system in its response to X‐rays and structural properties that is most strongly revealed in Rb‐substituted compounds whose X‐ray sensitivity outperforms…

• VF
  Villum Fonden

  Award: 11744
• DL
  Diamond Light Source
• HF
  Hercules Foundation

  Award: HER/11/14
• EC
  European Commission

  Award: GA‐642196
• BF
  Belgian Federal Science Policy Office

  Awards: IAP-PH05, IAP‐PH05
• FW
  Fonds Wetenschappelijk Onderzoek

  Awards: HER/11/14, 12Y6418N, CASAS2, Meth/15/04, Meth/15/04, 1514220N, 1203719N, G.0962.13, CASAS2, G098319N
• KL
  KU Leuven

  Awards: C14/19/079, C14/19
• DF
  Danmarks Frie Forskningsfond
• VR
  Vlaamse regering

  Awards: CASAS2, Meth/15/04, Meth/15/04, CASAS2