Synthesis and photoelectrochemical properties of bismuth thioiodide

The method of chemical deposition of monocrystalline bismuth thioiodide BiSI needles with a high quantum efficiency of photocurrent generation (up to 55 %) in aqueous solutions of electrolytes has been developed. It was revealed that the introduction of sulfide and iodide anions into the electrolyte solution leads to an increase of the absolute photocurrent values, as well as the presence of sulfide ions causes the significant (about 0.5 V) shift of BiSI bands energy towards more negative electrode potentials. The observed effect is of interest for increasing the photovoltage of solar cells based on BiSI and can find application in heterogeneous sensitized systems for increasing the efficiency of photoelectrons injection from a narrow-band sensitizer into a matrix of a wide-bandgap semiconductor.