Synthesis of quasi-spherical AgBr microcrystal via a simple ion-exchange route

• AgBr microcrystal was synthesized through a simple ion-exchange route.
• AgCl was used as the template and CTAB was the Br source.
• AgBr microcrystal was quasi-spherical with a diameter of approximately 5 μm.
• AgBr absorbed solar energy with wavelengths shorter than 480 nm.

Uniform quasi-spherical silver bromide (AgBr) microcrystal was synthesized through a simple ion-exchange route, in which silver chloride (AgCl) was used as the template and cetyltrimethyl ammonium bromide (CTAB) was the Br source. AgBr microcrystal was quasi-spherical with a diameter of approximately 5 μm in the synthesis, CTAB molecules slowly released Br− under hydrothermal condition, and then an ion-exchange reaction with Cl− proceeded at the AgCl surface at the initial stage, Br− then diffused from the AgCl surface to the interior. Finally, Cl− in AgCl structure was consumed completely by Br−, producing pure AgBr. The AgBr product can absorb solar energy with wavelengths shorter than 480 nm, which is consistent with previously reported results.