Seed Layer-Assisted Growth of Bi2s3 Nanorod Films for Efficient Photoelectrochemical Water Splitting

Nanocrystalline Bi<inf>2</inf>S<inf>3</inf> thin films show significant potential for efficient photoelectrochemical (PEC) water splitting applications. However, traditional chemical bath deposition (CBD) methods face challenges such as poor adhesion, limited thickness, and the need for multiple depositions. This study addresses these issues by introducing a seed layer-assisted growth method, utilizing Sb<inf>2</inf>S<inf>3</inf> as the seed layer to enhance the synthesis of uniform and strongly adherent Bi<inf>2</inf>S<inf>3</inf> nanorod films on FTO-coated glass substrates. Three types of Bi<inf>2</inf>S<inf>3</inf> films were prepared: pristine Bi<inf>2</inf>S<inf>3</inf>, Bi<inf>2</inf>S<inf>3</inf> on an Sb<inf>2</inf>S<inf>3</inf> seed layer, and Bi<inf>2</inf>S<inf>3</inf> with the addition of SbCl<inf>3</inf> to the starting solution. The pristine Bi<inf>2</inf>S<inf>3</inf> films formed nanorods 50–100 nm in length, with a direct bandgap of 1.25 eV, and a photocurrent density of 4.6 mA/cm2 at 1 V vs Ag/AgCl. The Bi<inf>2</inf>S<inf>3</inf> films deposited on an Sb<inf>2</inf>S<inf>3</inf> seed layer exhibited improved nanorod density and size (100–150 nm) and an increased photocurrent of 10.0 mA/cm2 at 1 V vs Ag/AgCl. Conversely, the addition of SbCl<inf>3</inf> to the starting solution resulted in smaller nanorods (50–100 nm), a higher energy gap of 1.32 eV, and a reduced photocurrent density of 7.0 mA/cm2. These findings demonstrate that the use of an Sb<inf>2</inf>S<inf>3</inf> seed layer prior to Bi<inf>2</inf>S<inf>3</inf> growth significantly enhances the nanorod density and improves both the physical and PEC properties of the films, making this method a promising approach for developing more efficient PEC water-splitting devices. This seed layer approach provides a pathway for the large-scale development of various semiconductor thin films for photoelectrochemical and other optoelectronic device applications. © 2024