SKKU Advanced Institute of Nanotechnology, and Department of Chemistry and BK-21 School of Chemical Materials Science, Sungkyunkwan University, Suwon 440-746, Korea.
Phys Chem Chem Phys. 2012 Mar 14;14(10):3576-82. doi: 10.1039/c2cp23545e. Epub 2012 Feb 6.
In this paper, we demonstrate that Cr(2)O(3), a visible absorbing insulator, can be used as an efficient blocking layer material for the anode of dye-sensitized solar cells (DSSCs). We prepared SnO(2) electrodes surface-modified with Cr(2)O(3) with various Cr/Sn ratios and studied the effect of the modification on the performance of DSSCs. DSSCs with Cr/Sn ratios 0.02, 0.05, and 0.10 showed increased overall photon-to-electricity conversion efficiency from that of pure SnO(2). Especially, the DSSC with the Cr/Sn ratio 0.02 showed a remarkably large increase by 55%. The electrode materials were analyzed by powder X-ray diffraction, transmission electron microscopy, N(2) adsorption studies, and UV-Vis diffuse reflectance spectroscopy. The Cr-containing species appears to be Cr(2)O(3) nanoparticles, spread evenly on the SnO(2) nanoparticles and filling the gap space between SnO(2) particles. The electrochemical properties of the electrodes were characterized by Mott-Schottky plots and electrochemical impedance spectroscopy. As the Cr-content increases, the flat-band potential is negatively shifted. The impedance spectroscopy data show that Cr/Sn = 0.02 and 0.05 samples have lower charge transport resistance at the electrode, which can be explained by the rise of the conduction level due to the charge transfer from the more basic Cr(2)O(3) nanoparticles to SnO(2) nanoparticles. These observations corroborate with the trends of the short-circuit current and the open-circuit voltage of the DSSCs.
本文证明了 Cr(2)O(3)（一种可见吸收的绝缘体）可用作染料敏化太阳能电池（DSSC）阳极的高效阻挡层材料。我们制备了具有不同 Cr/Sn 比的 Cr(2)O(3)修饰的 SnO(2)电极，并研究了修饰对 DSSC 性能的影响。Cr/Sn 比为 0.02、0.05 和 0.10 的 DSSC 的整体光子到电子的转换效率均高于纯 SnO(2)的效率。特别是，Cr/Sn 比为 0.02 的 DSSC 的效率提高了 55%。通过粉末 X 射线衍射、透射电子显微镜、N(2)吸附研究和 UV-Vis 漫反射光谱对电极材料进行了分析。含 Cr 物质似乎是 Cr(2)O(3)纳米颗粒，均匀地分散在 SnO(2)纳米颗粒上并填充了 SnO(2)颗粒之间的间隙空间。通过 Mott-Schottky 图和电化学阻抗谱对电极的电化学性能进行了表征。随着 Cr 含量的增加，平带电位向负方向移动。阻抗谱数据表明，Cr/Sn = 0.02 和 0.05 样品在电极处具有较低的电荷传输电阻，这可以通过 Cr(2)O(3)纳米颗粒向 SnO(2)纳米颗粒的电荷转移导致导带能级升高来解释。这些观察结果与 DSSC 的短路电流和开路电压的趋势相符。
