Fabrication of a preferentially -oriented Sb2Se3 thin film on diverse substrates and its application in photoelectrochemical water reduction†
Layered Sb2Se3 consists of infinite chains of repeating Sb4Se6 units stacked along the c-axis via Sb–Se covalent bonds, whereas they are linked by van der Waals force along the a-axis and b-axis. It usually tends to grow along the [hk0] orientation with low surface energy. However, -oriented growth, which efficiently enhances charge transport, is often considered unstable due to its high surface energy. Herein, we propose a growth method to fabricate Sb2Se3 thin films with the preferential -orientation on various substrates (Mo, MoSe2, SLG, NiO, SiO2 and FTO). This crystal facet design of preferentially -oriented Sb2Se3 exposes the majority of the nanoribbons vertically aligned to the substrate, and thus maximally improves the charge transport, which may find applications in diverse optoelectronic devices. We confirmed their performance in photoelectrochemical water reduction. The preferentially -oriented Sb2Se3 photocathode exhibited an impressive photocurrent density of −20.5 mA cm−2 at 0 V vs. RHE and a maximum photocurrent density of −28 mA cm−2 at −0.2 V vs. RHE under 1 sun AM 1.5 G illumination. Thus, the successful use of this -Sb2Se3 photocathode paves the way for the development of high-efficiency Sb2Se3-based devices for optoelectronic applications.