Multidimensional ZnO Architecture for Dye-Sensitized Solar Cells with High-Efficiency up to 7.35%
Multidimensional ZnO Architecture for Dye-Sensitized Solar Cells with High-Efficiency up to 7.35%
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多维%20ZnO%20Architecture%20for%20染料敏化%20Solar%20Cells%20with%20High-Efficiency%20up%20to%207.35%
DOI：
10.1002/aenm.201301802
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发表时间：
2014-06-01
影响因子：
27.8
通讯作者：
Chen, Jian-Feng
中科院分区：
文献类型：
--
作者：
Lu, Xin-Hong;Zheng, Yan-Zhen;Chen, Jian-Feng
DOI：10.1002/aenm. 201301802由纳米晶体提供的亚微米尺寸和大表面积引起。[8，13]然而，在即使用高性能2D ZnO NS和3D ZnO NA构造的光阳极中，难以同时实现上述三个高效率的先决条件，因为2D NS结构总是具有纳米级尺寸且光差，然而，沿着3D NA的Z字形电子传输路径沿着通常会延迟电子传输，并因此在3D NA内引起电子复合。在某种程度上，膜。[8，10]一般来说，ZnO结构不能提供高性能DSC所需的所有上述特性，因此很少有基于ZnO的DSC可以具有超过7%的PCE。[13]因此，基于多维（MD）ZnO架构的光阳极的制造由具有协同效应的特定特征的不同一维纳米结构组成，提供了一种更好的方法来实现高PCE。[4，15，16]事实上，我们之前已经证明，基于由3D-纳米棒-聚集体覆盖层和0D-纳米微晶石底层组成的MD ZnO结构的DSC产生比基于单层纳米棒-聚集体或纳米微晶石的那些高得多的PCE。[4]尽管如此，MD ZnO电池的整体PCE仍然很低，并且精细设计和调整ZnO光电阳极架构以同时最大化突出PCE的关键特征仍然是一个巨大的挑战。在这里，我们报告了一种创新的MD ZnO结构的制备与2D ZnO NS和3D ZnO NAs的组合，其中ZnO NS不仅作为连接ZnO NA框架的桥梁，在膜内形成有利的电子传输通道，而且还作为构建块，以扩大染料吸附的总表面积，并提供一个随机打开的结构，以更好地同时电解质渗透。在这种情况下，在这项工作中的一个关键技巧是同步调整的表面积和电子传输性能的MD ZnO架构，通过控制的ZnO纳米结构的密度与保留相对较强的光散射所提供的ZnO纳米结构。在最佳条件下，ZnO NA/NS复合结构光阳极的光电转换效率达到6.66%，比ZnO NA光阳极提高了64.0%。各种分析证实，这种MD ZnO NA/NS复合光阳极的光伏性能增强主要是由于大的表面积、有效的电子传输和强的光散射能力的优异组合。为了进一步提高PCE，在制备优化的ZnO NA/NS薄膜之前，在衬底上铺设了一层致密的0D ZnO纳米线。这导致了令人印象深刻的7.35%的PCE，这非常接近有史以来报道的ZnO基DSC的PCE记录（7.5%）。[17]染料敏化太阳能电池（DSC）是重要的低成本光伏器件，在解决许多环境和能源问题方面显示出巨大的前景。[1]DSC通常是由涂覆有染料分子的多孔光阳极膜、碘化物/三碘化物电解质和铂对电极组成的双晶结构太阳能电池。[2]除了寻找更高效、更稳定的染料外，光阳极结构的设计和改进也引起了人们的极大关注。[3]通常，高比表面积、快速电子传输和出色的光散射能力是高效DSC中优异光阳极的先决条件。[4]在过去的十年里…
DOI: 10.1002/aenm. 201301802 arisen from the sub-micrometer size and large surface area provided by the nanocrystals.[8, 13] In photoanodes constructed even with high-performance 2D ZnO NSs and 3D ZnO NAs, however, it is difficult to simultaneously achieve the aforementioned three prerequisites for a high efficiency since the 2D NS structure always possesses nanoscale size with poor light-scattering capability while the zigzag electron transport pathway along the 3D NAs often retards the electron transport and thus inflicts electron recombination within the electrode film to some extent.[8, 10] Generally speaking, ZnO architectures cannot provide all the abovementioned properties required for high-performance DSCs, and hence few DSCs based on ZnO could have PCEs exceed 7%.[13] Therefore, the fabrication of photoanodes based on multidimensional (MD) ZnO architectures composed of different monodimensional nanostructures of specific features with synergistic effects offer a better approach to high PCEs.[4, 15, 16] Indeed, we have previously demonstrated that DSC based on a MD ZnO architecture consisting of a 3D-nanorod-aggregate overlayer and a 0D-nanocrystallite underlayer yielded a much higher PCE than those based on single-layered nanorod-aggregates or nanocrystallites.[4] Nevertheless, the overall PCE of the MD ZnO cells is still low and it is still a great challenge to finely design and tune the ZnO photoanode architecture to simultaneously maximize the key features for outstanding PCEs. Here, we report the preparation of an innovative MD ZnO architecture with combination of 2D ZnO NSs and 3D ZnO NAs, in which the ZnO NSs act not only as bridges connecting the ZnO NA-framework to form favorable electron transport channels within the film, but also as building blocks to enlarge the overall surface area for dye-adsorption and to provide a randomly-opened structure for a better concurrent electrolyte penetration. In this context, a key trick in this work is to synchronously tune the surface area and electron transport property of the MD ZnO architecture by controlling the density of the ZnO NSs with retention of relatively strong light-scattering provided by the ZnO NAs. Under optimal condition, an overall PCE of 6.66% was achieved for a photoanode based on the ZnO NA/NS composite architecture, a noticeable improvement by 64.0% in comparison with that of the corresponding cell fabricated with ZnO NA photoanode. Various analyses confirmed that the photovoltaic performance enhancement in such a MD ZnO NA/NS composite photoanode was mainly due to the excellent combination of large surface area, effective electron transport, and strong light-scattering capability. To further improve the PCE, a compact layer of 0D ZnO nanocrystal was then paved on the substrate before fabricating the optimized ZnO NA/NS film. This led to an impressive PCE of 7.35%, which is very close to the record PCE (7.5%) of ZnO-based DSCs ever reported.[17]Dye-sensitized solar cells (DSCs) are important low-cost photovoltaic devices that show great promise to solve many environmental and energy problems.[1] DSC is typically a sandwich-structure solar cell consisting of a porous photoanode film coated with dye molecules, an iodide/triiodide electrolyte and a platinum counter electrode.[2] Apart from the search for more efficient and stable dyes, the design and modification of the photoanode architecture has also attracted great attention.[3] In general, high specific surface area, fast electron transport and outstanding light-scattering capability are prerequisites for an excellent photoanode in highefficiency DSCs.[4] In the past decade …