Jung Hyejin, Chae Sang Youn, Shin Changhwan, Min Byoung Koun, Joo Oh-Shim, Hwang Yun Jeong
†Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 136-791, Republic of Korea.
‡Korea University of Science and Technology, Daejeon 305-350, Republic of Korea.
ACS Appl Mater Interfaces. 2015 Mar 18;7(10):5788-96. doi: 10.1021/am5086484. Epub 2015 Mar 9.
BiVO4 has been formed into heterojunctions with other metal oxide semiconductors to increase the efficiency for solar water oxidation. Here, we suggest that heterojunction photoanodes of Si and BiVO4 can also increase the efficiency of charge separation and reduce the onset potential of the photocurrent by utilizing the high conduction band edge potential of Si in a dual-absorber system. We found that a thin TiO2 interlayer is required in this structure to realize the suggested photocurrent density enhancement and shifts in onset potential. Si/TiO2/BiVO4 photoanodes showed 1.0 mA/cm(2) at 1.23 V versus the reversible hydrogen electrode (RHE) with 0.11 V (vs RHE) of onset potential, which were a 3.3-fold photocurrent density enhancement and a negative shift in onset potential of 300 mV compared to the performance of FTO/BiVO4 photoanodes.
BiVO₄已与其他金属氧化物半导体形成异质结，以提高太阳能水氧化效率。在此，我们提出，在双吸收体系统中利用Si的高导带边缘电位，Si和BiVO₄的异质结光阳极也可以提高电荷分离效率并降低光电流的起始电位。我们发现，在这种结构中需要一层薄的TiO₂中间层，以实现所提出的光电流密度增强和起始电位的偏移。Si/TiO₂/BiVO₄光阳极在相对于可逆氢电极（RHE）为1.23 V时显示出1.0 mA/cm²的光电流密度，起始电位为0.11 V（相对于RHE），与FTO/BiVO₄光阳极的性能相比，光电流密度提高了3.3倍，起始电位负移了300 mV。
