A hydrophobic polymer stabilized p-Cu₂O nanocrystal photocathode for highly efficient solar water splitting

For the first time, a compact hydrophobic layer composed of a macromolecular polymer was applied to inhibit the inactivation of cuprous oxide. In addition, 50 nm thick silver was sputtered on an FTO substrate as a reflective layer to enhance photon utilization efficiency, while n-TiO₂ forms a semiconductor heterojunction to effectively separate photo-generated carriers. After depositing Pt as a hydrogen evolution catalyst, a photocurrent density of -5.5 mA cm^-2 was finally obtained, and retained 98% photo-stability after 6 hours, and the IPCE summit reached 68.3% at 415 nm.