碳纳米管异质结构的控制制备及其在光电转换器件中的应用

In order to moderate global reliance on exhaustible natural resources and their environmentally hazardous combustion, more scientific efforts should be directed towards exploring the novel approaches of energy generation and utilization. Solar cell, that converts the energy of light directly into electricity by the photovoltaic effect, has been regarded as the promising candidate of the renewable energy sources. Of which, conventional silicon-based solar cell devices that constructed from platform p-n junctions have attracted the most attentions due to their simple preparation and high photovoltaic efficiency of 25%. However, the high cost and low theoretical efficiency due to high-purity single-crystalline silicon are the tremendous obstacles for their further applications on a larger scale...Single-walled carbon nanotubes (SWNTs) have attracted enormous attention as model systems for nanoscience and nanotechnology because of their unique chemical and physical properties. Meanwhile, series of growth methodologies were established to accurately control SWNT's structures like diameter, orientation, metallic (m-)/ semiconducting (s-) and even chirality. According to the one dimensional structures and different electric conductance (m-/s-), SWNTs and their heterojunctions in particular present a great possibility as the potential building blocks for the photovoltaic devices. Herein, this proposal will focus on the rational design and controlled fabrication of SWNT-based heterojunctions, including radial heterojunctions, axial heterojunctions, heterojunction vertical arrays and horizontal arrays. In addition, the integrated photovoltaic devices based on SWNT-based heterojunctions would be fabricated to improve the conversion efficiency and reduce the cost. So, we will divide into three steps to perform this proposal: 1) The controlled fabrication of SWNT-based radial/axial heterojunctions using the CVD growth method and chemical self-assembly method; 2) The controlled fabrication of SWNT-based heterojunction vertical/ horizontal arrays with the CVD growth method and 'post-growth' method; 3) The preparation of tandem devices based on SWNT-based heterojunction and the measurement of its photovoltaic performances. We hope that photovoltaic devices with SWNT-based heterojunction would support the full of opportunities for practical and socially significant applications.

开发具有低成本和高稳定性能的能源转换物质一直是材料领域长期的研究热点，本项目将主要探索碳纳米管在光电转换器件中的应用。由于半导体性碳纳米管的直接带隙大小一般在近红外光谱能段，很难在太阳光电池领域被广泛应用。为此，本项目提出从碳纳米管基异质结结构的设计和可控制备出发，探索其在光电转化器件研究中的应用。本项目拟在本研究小组前期工作的基础上：1）发展碳纳米管径向和轴向异质结的可控生长方法；2）在制备水平和竖直碳纳米管阵列的基础上，发展碳纳米管异质结的"后处理"制备方法；3）探索碳纳米管异质结在光电转换器件中的应用。

本项目的研究内容是单壁碳纳米管以及碳纳米管基异质结的可控制备及其在光电转换器件中的应用。碳纳米管的能带取决于其手性，因此碳纳米管的手性控制制备极其关键。本项目的研究主要集中在单壁碳纳米管的控制制备，包括密度、管径、导电属性和手性的控制，以及碳纳米管在近红外探测和光电转换方面的器件应用。通过项目的实施，实现了高密度超长单壁碳纳米管水平阵列的制备，密度大于130根/微米；实现了碳纳米管水平阵列中半导体性碳管的富集（密度大于100根/微米，同时半导体管含量大于90%）；实现了碳纳米管的手性可预测生长，包括（2m, m）型以及（n, n-1）型碳纳米管；发展了碳纳米管水平阵列的快速高通量光学表征方法；实现了基于单壁碳纳米管水平阵列的近红外光探测。项目共发表学术论文17篇，其中期刊影响因子大于7的16篇；申请专利6项；作国内外学术会议邀请报告14次，其中国际会议11次，国内会议3次；培养博士研究生8名，出站博士后1名。