Self-oriented Sb2Se3 nanoneedle photocathodes for water splitting obtained by a simple spin-coating method

Synthesis of one-dimensional nanostructured chalcogenide compounds using nontoxic and abundant constituents provides an important pathway to the development of commercially feasible photoelectrochemical water splitting. In this study, grass-like Sb2Se3 nanoneedle arrays are successfully fabricated on a substrate via a facile spin-coating method without any complicated processes such as templating, seed formation, or use of a vapor phase. Preferential [001] growth of the initial single-crystalline Sb2Se3 occurs during the first spin-coating, but interfacial defects are generated upon subsequent spin-coating iterations, resulting in annual-ring-like growth of Sb2Se3 nanoneedles. After sequential surface modification with TiO2 and Pt, the resistance to charge transfer from the photoelectrode to the electrolyte decreases significantly, yielding a remarkable record-high photocurrent of 2 mA cm(-2) at 0 V-RHE (4.5 mA cm(-2) at -0.2 V-RHE).