Center for Low-dimensional Materials, Micro-nano Devices and System, Changzhou University, Changzhou 213164, China.
Nanoscale Res Lett. 2013 Jan 3;8(1):9. doi: 10.1186/1556-276X-8-9.
High performance is expected in dye-sensitized solar cells (DSSCs) that utilize one-dimensional (1-D) TiO2 nanostructures owing to the effective electron transport. However, due to the low dye adsorption, mainly because of their smooth surfaces, 1-D TiO2 DSSCs show relatively lower efficiencies than nanoparticle-based ones. Herein, we demonstrate a very simple approach using thick TiO2 electrospun nanofiber films as photoanodes to obtain high conversion efficiency. To improve the performance of the DSCCs, anatase-rutile mixed-phase TiO2 nanofibers are achieved by increasing sintering temperature above 500°C, and very thin ZnO films are deposited by atomic layer deposition (ALD) method as blocking layers. With approximately 40-μm-thick mixed-phase (approximately 15.6 wt.% rutile) TiO2 nanofiber as photoanode and 15-nm-thick compact ZnO film as a blocking layer in DSSC, the photoelectric conversion efficiency and short-circuit current are measured as 8.01% and 17.3 mA cm-2, respectively. Intensity-modulated photocurrent spectroscopy and intensity-modulated photovoltage spectroscopy measurements reveal that extremely large electron diffusion length is the key point to support the usage of thick TiO2 nanofibers as photoanodes with very thin ZnO blocking layers to obtain high photocurrents and high conversion efficiencies.
由于具有有效的电子传输性能，人们对一维（1-D）TiO2 纳米结构的染料敏化太阳能电池（DSSCs）寄予厚望。然而，由于染料吸附性低，主要是因为其表面光滑，一维 TiO2 DSSCs 的效率相对低于基于纳米颗粒的 DSSCs。在此，我们展示了一种非常简单的方法，使用厚 TiO2 静电纺纳米纤维膜作为光阳极以获得高转换效率。为了提高 DSCCs 的性能，通过将烧结温度提高到 500°C 以上，获得了锐钛矿-金红石混合相 TiO2 纳米纤维，并通过原子层沉积（ALD）方法沉积了非常薄的 ZnO 薄膜作为阻挡层。在 DSSC 中，使用约 40-μm 厚的混合相（约 15.6wt.%金红石）TiO2 纳米纤维作为光阳极和 15nm 厚的致密 ZnO 薄膜作为阻挡层，光电转换效率和短路电流分别测量为 8.01%和 17.3mA/cm2。强度调制光电流谱和强度调制光电压谱测量表明，大的电子扩散长度是关键，支持使用厚的 TiO2 纳米纤维作为光阳极，并使用非常薄的 ZnO 阻挡层，以获得高的光电流和高的转换效率。
