A hybrid halobismuthate light-harvesting material with an optical band gap of 1.70 eV

Abstract

A new organic–inorganic hybrid material (C₁₅H₁₄N₄)BiBr₅·H₂O with an optical band gap of 2.24 eV, having 1-D chains of bromobismuthate anions in its composition, has been obtained from an aqueous solution and characterized. The partial replacement of Br by I resulted in the formation of a thermally stable (<155 °C) black compound (C₁₅H₁₄N₄)BiBrI₄·H₂O with an optical band gap of 1.70 eV, which can be proposed as a promising light-harvesting material for dye-sensitized solid-state solar cells. Further replacement of Br by I results in the formation of red-orange colored (C₁₅H₁₄N₄)BiI₅ with a band gap of 2.10 eV.