Preparation of nano dumbbell-shaped silver bismuth iodide perovskite hybrids and their enhanced photocurrent properties

Abstract

Dumbbell-like silver bismuth iodide perovskite heterostructures were fabricated via the growth of heterogeneous silver using a modified emulsion method. Owing to the immiscibility between DMF and hexane, the silver bismuth iodide precursors in DMF could be dispersed as microscopic droplets in hexane under vigorous stirring. Subsequently, the addition of acetone as a demulsifier provided the driving force for crystallization to form dumbbell-shaped silver bismuth iodide perovskite heterostructures. In this synthesis, we added a high concentration of Ag precursors to DMF, which influenced the morphology changes to form a silver-metal-head dumbbell-shaped silver bismuth iodide perovskite hybrid system. However, in the dumbbell heterostructure, a large silver domain was exclusively grown on a single side of the AgBi₂I₇ system. Further, the as-prepared dumbbell-shaped AgBi₂I₇ heterostructure sample was used to fabricate a photo-sensitive device and its time-dependent photocurrent properties were analysed. The dumbbell-shaped metal-perovskite heterostructure sample exhibited a higher photocurrent magnitude of ∼21 and 70 μA for 0.1 and 0.2 V bias voltage, with a high ON–OFF ratio of 3.1 × 10⁴ and 3.2 × 10⁴, respectively. The improved photocurrent indicates that the transfer of photogenerated electrons was facilitated from the perovskite system to the metal head.