复合纳米纤维膜基低品位多能源换能器设计的基本科学问题研究

Multifunctional energy conversion device is a kind of integrated device including many kinds of energy conversion functionalities based on the low-grade energy. The solar energy, thermal energy, mechanical energy and chemical energy are the common low-grade energies. Conventional ingoganic photoelectric, thermoelectric and piezoelectric materials based low-grade energies generally exhibit a good conversion efficiency, but they are difficult to be processed. In this project, we have developed a one-dimensional functional polymer/inorganic nanocomposites for photoelectric, thermoelectric and piezoelectric conversion applications to be as a multifunctional energy conversion device. The conversion efficiency could be enhanced by the quantum confinement effect and synergistic effect in this kind of one-dimensional nanocomposites. We would study the effects of compostion,structure, doping effect of polymers, shape, type and distribution of inorganic component in the 1D nanocomposites on the photoelectric, thermoelectric and piezoelectric performance of the composites, we would also study the effect of the thickness and the pore size of the 1D nanocomposite membrane, the assembly of the membrane and the processing mode of the device on the conversion efficiency of the multifunctional energy conversion device. The ultimate object is to achieve the matching of the different kinds of nanocomposites and prepare a new kind of multifunctional energy conversion device with high energy conversion effeciency.

多功能换能器是指将多种低品位能源转换功能集成于一个器件所形成一种新型能量转换装置。低品位能源主要包括太阳能、热能、机械能、化学能等。目前，传统的基于低品位能源的无机光电、热电以及压电材料具有较好的转换效率，但是器件制备较为困难。在本项目中，我们提出利用多种一维功能高分子/无机复合纳米材料分别做为光电、热电以及压电材料并组装成多功能换能器。通过二次量子限域效应以及多组分材料之间的协同作用提高其光电、热电以及压电转换效率。研究高分子/无机复合一维纳米结构材料的组成、结构、复合材料中高分子的掺杂行为、复合材料中无机纳米组分的形态、种类、分布等对复合材料的光电、热电以及压电性能的影响，研究复合一维纳米纤维膜的厚度、孔隙率、膜的组装方式以及器件加工方式对多功能换能器能量转换效率的影响。最终实现在多能源驱动下电功能多元复合纳米纤维材料的相互匹配，制备出一类具有较高能量转换效率的多功能换能器。

随着经济的发展，传统的煤、石油、天然气等高品位化石能源不但趋于枯竭，使用过程中对环境造成的污染也不容忽视。近年来，对太阳能、热能、机械能等低品位能源的利用引起了人们的关注，这些能源来源广泛，但转换效率较低，难以用传统的发电机进行收集。研究表明，具有纳米结构的新型换能器能够将这类低品位能源转化为电能。利用高压静电纺丝技术制备的纳米纤维膜轻便柔软，是制备这种新型低品位换能器的潜力材料。.本项目中，我们以静电纺丝为主要技术手段，成功制备了一系列以聚合物纳米纤维为基底复合纳米纤维膜，这些材料展现了良好的光电、热电以及压电性能。具体来说，我们制备了碳纳米纤维/过渡金属化合物复合纳米纤维，可用作染料敏化太阳能电池，具有优良的光电转换效应；我们制备了导电聚合物/金属复合纳米纤维膜，研究了其热电性质；我们还制备了压电聚合物/压电晶体复合纳米纤维膜，提高了其压电转换效率，能够将声波振动等机械能转换为电能。这些材料能够实现光能、热能和机械能这些低品位能源的利用。