TiO2 multilayer thick films (up to 4 µm) with ordered mesoporosity: influence of template on the film mesostructure and use as high efficiency photoelectrode in DSSCs
TiO2 multilayer thick films (up to 4 µm) with ordered mesoporosity: influence of template on the film mesostructure and use as high efficiency photoelectrode in DSSCs
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DOI：
10.1039/c1jm10288e
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发表时间：
2011-05
影响因子：
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通讯作者：
J. Dewalque;R. Cloots;F. Mathis;O. Dubreuil;N. Krins;C. Henrist
中科院分区：
文献类型：
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作者：
J. Dewalque;R. Cloots;F. Mathis;O. Dubreuil;N. Krins;C. Henrist
介孔锐钛矿薄膜是非常有前景的染料敏化太阳能电池电极材料。随机取向的纳米晶TiO2颗粒通常用于制备厚度为10-15μm的光电极。模板辅助浸涂技术用于获得具有有序孔隙率的薄膜。然而，通过溶液浸涂制备的单层薄膜活性材料含量低且表面积有限，导致光伏性能较差。因此，需要多层沉积工艺来增加薄膜厚度和表面积。多层浸涂程序已被报道，但通常的特点是随着层数的增加，参数（粗糙度、表面积、光伏性能）的演变缺乏线性。在本文中，报道了一种基于浸涂的多层沉积技术。首先，从长程有序、孔隙率、孔径和孔隙连通性方面研究了模板对薄膜组织和孔隙率的影响。透射电子显微镜 (TEM)、大气孔隙椭圆光度法 (AEP) 和紫外可见吸收光谱 (UV-vis) 等不同技术已被用来描述厚度为 1 µm 的薄膜的微观结构特征。选择染料负载量最高的薄膜，其厚度逐渐增加至 4 µm。最后，厚膜（1 至 4 µm）的光伏性能与 N-719 染料结合进行了评估，与文献报道的值相比，显示出优异的效率（6.1%）。这种介观结构薄膜的光伏性能与通常用于 DSSC 的 TiO2 纳米粒子薄膜进行了比较。
Mesoporous anatase thin films are very promising materials to act as electrode in dye-sensitized solar cell. Randomly oriented nanocrystalline TiO2 particles are usually used to prepare photoelectrodes with a thickness of 10–15 µm. Template-assisted dip-coating techniques are used to obtain thin films with ordered porosity. However, monolayer films prepared by dip-coating from a solution suffer from a low quantity of active material with a limited surface area, leading to poor photovoltaic performances. Therefore a multilayer deposition process is needed to increase the film thickness along with the surface area. Multilayer dip-coating procedures have already been reported but are usually characterized by a lack of linearity in the evolution of parameters (roughness, surface area, PV performances) as the number of layer increases. In this paper, a dip-coating-based multilayer deposition technique is reported. First, the influence of the template on the film organization and porosity is studied in terms of long-range order, percentage of porosity, pore size and pores connectivity. Different techniques such as transmission electron microscopy (TEM), atmospheric poroellipsometry (AEP) and UV-visible absorption spectroscopy (UV-vis) have been used to describe the microstructural features of the films with a thickness of 1 µm. The film exhibiting the highest dye loading was selected and its thickness gradually increased up to 4 µm. Finally, the photovoltaic performances of the thick films (1 to 4 µm) have been evaluated in combination with the N-719 dye and show excellent efficiency (6.1%) when compared to values reported in the literature. Such mesostructured films are compared in terms of photovoltaic performance with TiO2 nanoparticles films, generally used in DSSC.