Morphologically and Compositionally Controlled Cs2SbBr6 by Bi and Ag Substitution

Morphology-controlled Cs2SbBr6 crystals are synthesized by Bi- and Ag-substitution of the precursor solution. X-ray diffraction (XRD) together with Raman spectroscopy confirms the lattice tilting and symmetry changes with the dominant appearance of higher index facets by Bi substitution. Ag substitution does not induce crystal symmetry changes in the Cs2BBr6 (B = Sb or Bi) phase, but results in highly defective structures hindering the formation of a smooth surface during the crystal growth. Successful substitution of Bi and limited substitution of Ag into Cs2SbBr6 is also confirmed by energy dispersive X-ray spectroscopy (EDX). This research provides design principles and practical examples of how to control the morphology of Cs2SbBr6 crystals with structural defects and multiphase formation.