ALD TiO2 Passivation of Sb2S3 Photocathodes for Photoelectrochemical Hydrogen Production

Project overview. Photoelectrochemical (PEC) water splitting is a promising route for converting sunlight directly into renewable hydrogen. Antimony sulfide (Sb2S3) is an attractive visible-light semiconductor, but its performance as a photocathode is often limited by surface/interface recombination, inefficient charge transfer, and photocorrosion in aqueous electrolytes. This MSc project will investigate ultrathin TiO2 layers deposited by atomic layer deposition (ALD) as controlled passivation and protection layers on Sb2S3. The main goal is to understand how TiO2 thickness and deposition conditions influence interfacial charge transport, recombination, photocurrent, and operational stability, while distinguishing genuine PEC activity from degradation-related current.  

Research approach. The student will first establish a reproducible Sb2S3 reference photocathode and then perform a focused ALD optimization by varying selected parameters such as TiO2 thickness/number of cycles, deposition temperature, and post-treatment. The resulting films will be characterized using techniques such as SEM, XRD, UV-Vis spectroscopy, Raman spectroscopy, and Photoluminescence spectroscopy. PEC behavior will be evaluated using dark/light linear sweep voltammetry, chopped-light measurements, chronoamperometry, electrochemical impedance spectroscopy, and stability tests.  

Expected outcomes and training. The project is expected to identify the ALD conditions that most strongly affect protection, transport resistance, recombination, and stability of Sb2S3 photocathodes. The student will gain hands-on experience in thin-film fabrication, ALD interface engineering, semiconductor characterization, electrochemistry, photoelectrochemistry, experimental design, data analysis, and scientific interpretation. Strong and complete results may contribute to a peer-reviewed publication. 

Candidate profile. We welcome motivated MSc students in materials science, chemistry, chemical engineering, nanotechnology, applied physics, renewable energy, electrochemistry, or a related field. Previous experience with semiconductors, thin films, or electrochemistry is an advantage but not required. Scientific curiosity, careful laboratory work, reliability, and willingness to troubleshoot experiments are especially important. 

The work will be carried out in the newly built laboratories at imec in EnergyVille campus, Genk, working within the solar fuels team on power to molecules strategy group. 

Practical information