| 초록 |
Development of new photoelectrode is crucial to enhance solar water-splitting efficiency. Herein, we report a novel solution-processed copper-aluminate (CuAl2O4, CAO) film as a photocathode for photoelectrochemical water-splitting. Importantly, we found that lithium-ion (Li+) incorporation onto CAO has profound effects. It improves the light absorption, charge transport/transfer properties. In particular, the bandgap value reduced from 1.9 to 1.5 eV. Additionally, the Li+-activated CAO photocathode exhibited a photocurrent density (Jph) -1.4 mA/cm2 at 0.4 VRHE (faradaic efficiency: ~ 70%) under 1 sun illumination, which is 9 times higher than that of the pristine CAO. Further, the Jph of the Li+-activated CAO photocathode increased to -5.1 mA/cm2 by coupling with CuO underlayer, which is the highest value achieved among all the spinel-based-photocathodes. Our Li+ activation method can be extended to other spinel oxides (CuBi2O4, CuFe2O4) achieving over two times higher performance. |
