Yu Qiang, Cao Chuanbao
Research Center of Materials Science, Beijing Institute of Technology, Beijing 100081, China.
J Nanosci Nanotechnol. 2012 May;12(5):3984-9. doi: 10.1166/jnn.2012.6197.
The splitting of water using photoelectrochemical (PEC) cells to produce hydrogen is one of the most sustainable forms of energy production and more and more 1-D nanostructrues semiconductors used as photoelectrodes have been studied extensively. However, it is not clear whether the photoconversion efficiencies of such nanostructure devices are limited by the architectures of the 1-D electrodes. Here, we explore the effect of the architecture like the length and width of ZnO nanorods on the PEC cells performance for the first time. The as-prepared nanorods have diameters of 40-50 nm and lengths of 400-800 nm. Preliminary measurements exhibit that the resulting electrodes have promising PEC properties. Mott-Schottky measurements give a flat-band potential of +0.10 V, a carrier density of 3.7 x 10(17) cm(-3), and a space-charge layer of 26 nm. The photocurrent of 800 nm-long nanorods shows 10 times higher than that of 400 nm-long ones, and an encouraging maximum photoconversion efficiency of 0.25% is obtained under illumination of 100 mW/cm2 (AM 1.5), which is among the highest reported for an undoped ZnO photoelectrode to date.
利用光电化学（PEC）电池分解水来制氢是最具可持续性的能源生产形式之一，越来越多用作光电极的一维纳米结构半导体受到了广泛研究。然而，这类纳米结构器件的光转换效率是否受一维电极结构的限制尚不清楚。在此，我们首次探究了诸如氧化锌纳米棒的长度和宽度等结构对PEC电池性能的影响。所制备的纳米棒直径为40 - 50纳米，长度为400 - 800纳米。初步测量表明，所得电极具有良好的PEC性能。莫特 - 肖特基测量给出的平带电位为 +0.10 V，载流子密度为3.7×10¹⁷ cm⁻³，空间电荷层为26纳米。800纳米长的纳米棒的光电流比400纳米长的纳米棒高出10倍，在100 mW/cm²（AM 1.5）光照下获得了令人鼓舞的0.25%的最大光转换效率，这是迄今为止未掺杂氧化锌光电极报道的最高值之一。
