Enhanced light harvesting and electron collection in quantum dot sensitized solar cells by TiO2passivation on ZnO nanorod arrays
Enhanced light harvesting and electron collection in quantum dot sensitized solar cells by TiO2passivation on ZnO nanorod arrays
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通过 ZnO 纳米棒阵列上的 TiO2 钝化增强量子点敏化太阳能电池中的光捕获和电子收集
DOI：
10.1007/s40843-016-9008-2
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
Zhiyong Liu
中科院分区：
文献类型：
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作者：
Haifeng Zhao;Qiang Wu;Juan Hou;Haibin Cao;Qun Jing;Rong Wu;Zhiyong Liu
光捕获和电子复合是决定量子点敏化太阳能电池（QD-SCs）能量转换效率的关键过程。众所周知，电荷在基于纳米棒阵列的良好构建的QDSC中容易传输。然而，这一优势可以大大削弱缺陷位于氧化锌（ZnO）阵列表面，允许更快的电子复合。因此，我们开发了一种复合纳米结构的ZnO纳米棒包覆正交配置的二氧化钛（TiO 2）纳米粒子，这是使用H3 BO 3和（NH 4）2 TiF 6的溶液合成。该复合纳米结构被设计成利用由纳米颗粒提供的增大的表面积和沿纳米棒的沿着改善的电子传输，以产生良好的电荷传输和光捕获。同时，TiO 2改性后的TiO 2/ZnO纳米棒阵列具有更少的复合中心（羟基），这导致ZnO纳米棒表面的电子捕获事件更少，从而可以实现更少的电荷复合和更长的电子寿命。结果表明，具有TiO 2纳米颗粒修饰的ZnO纳米棒阵列光电极的QDSC的PCE达到4.8%，与未修饰的太阳能电池的2.7%相比，其效率提高了约78%。
Light capture and electron recombination are the essential processes that determine power conversion efficiency (PCE) in quantum dot sensitized solar cells (QD-SCs). It is well known that charges are easily transported in well-built QDSCs based on nanorod arrays. However, this advantage can be drastically weakened by defects located at the zinc oxide (ZnO) array surface which permit faster electron recombination. Hence, we developed a composite nanostructure consisting of ZnO nanorods coated with orthorhombic configuration titanium dioxide (TiO2) nanoparticles, which were synthesized using a solution of H3BO3 and (NH4) 2TiF6. This composite nanostructure was designed to take the advantage of the enlarged surface area provided by the nanoparticles and improved electron transport along the nanorods, in order to yield good charge transport and light harvesting. At the same time, the TiO2/ZnO nanorod arrays have fewer recombination centers (hydroxyl groups) after TiO2 modification, which results in fewer electron trapping events at the ZnO nanorod surface; thereby, a reduced charge recombination and longer electron lifetime can be achieved. As a result, the PCE of the QDSCs with TiO2-nanoparticles-decorated ZnO nanorod arrays photoelectrode reaches 4.8%, which is~ 78% higher efficiency compared to 2.7% for solar cells without modification.