Photoelectrochemical Water Splitting with Thin Film Semiconductors

We investigate “emerging” semiconductor-based materials for photoelectrochemical water splitting, with a focus on those materials comprised of Earth-abundant elements and fabricated using simple and scalable methods. We have targeted copper oxides (Cu₂O and CuO) and copper sulfides (Cu₂S) due to the abundance of copper and facile preparation methods. Another promising material of interest to us is antimony selenide (Sb₂Se₃), which we found is resistant to photocorrosion in acidic solutions under full solar illumination (Figure 1). It is therefore a strong candidate for a practical, scalable material for solar energy conversion devices, receiving much attention from researchers around the world.

We also recently reported another antimony-based light-absorbing semiconductor, antimony sulfide (Sb₂S₃). Using a TiO₂ buffer layer and a platinum co-catalyst, a remarkable device performance was achieved by the Sb₂S₃ photocathodes for the first time (Figure 2). We hope that these efforts to explore and develop emerging light-absorbing materials pave the way for realizing the cost-effective production of chemical fuels from solar energy.