Nanoscale investigation on large crystallites in TiO2 nanotube arrays and implications for high-quality hybrid photodiodes
Nanoscale investigation on large crystallites in TiO2 nanotube arrays and implications for high-quality hybrid photodiodes
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DOI：
10.1007/s10853-012-6580-2
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发表时间：
2012-05
影响因子：
4.5
通讯作者：
A. Wisnet;M. Thomann;J. Weickert;L. Schmidt‐Mende;C. Scheu
中科院分区：
文献类型：
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作者：
A. Wisnet;M. Thomann;J. Weickert;L. Schmidt‐Mende;C. Scheu
在导电玻璃衬底上的TiO 2薄膜上制备的阳极氧化TiO 2纳米管阵列可以很容易地在混合太阳能电池等各种应用中实现。在这项研究中，我们集中在形态与内管直径约为30纳米，这是在尺寸的激子扩散长度的常见有机空穴导体。与透射电子显微镜相关的完整的管阵列的横截面制备已经进行，以获得局部信息的TiO 2纳米管和它们的安排，取决于阳极氧化电压。已经发现，随着阳极氧化电压的增加，随着长度的增加，沿着管壁的微晶是分散的并且尺寸为几百纳米沿着。发现了相邻管之间具有相似晶体取向的管间连接，这些连接导致了大面积的均匀取向。因此，与不同TiO 2-聚合物材料系统的报道值相比，膜内的晶界数量较低。使用阵列，混合二氧化钛太阳能电池制造，这表明高填充因子表明良好的电子传输。结果表明，高电子迁移率，是令人鼓舞的利用纳米管阵列在下一代光电子学。
Anodized TiO2nanotube arrays fabricated on a TiO2thin film on conducting glass substrates can be readily implemented in diverse applications like hybrid solar cells. In this study, we concentrate on morphologies with inner tube diameter being around 30 nm which is in dimension of the exciton diffusion length of common organic hole conductors. Cross-sectional preparation of the intact tube array in correlation with transmission electron microscopy has been performed to get local information on the TiO2nanotubes and their arrangements, depending on anodization voltage. Crystallites have been found to be anatase and in size of several hundred nanometers along tube walls with increasing length for increasing anodization voltages. Inter-tube connections with similar crystal orientations of adjacent tubes are found. These give rise to large areas of uniform orientation. Thus, the number of grain boundaries within the film is low compared to the reported values for different TiO2-polymer material systems. Using the arrays, hybrid TiO2solar cells were fabricated, which show high fill factors indicating good electron transport. The results suggest high electron mobility and are encouraging for a utilization of the nanotube arrays in next generation photovoltaics.