P3HT纳米线-CdSe/CuInSe2核壳纳米四角体耦连体异质结太阳能电池的构筑与性能研究

The performance of hybrid bulk-heterjunction solar cells (BSCs) is still confined by a bottleneck problem of low charge mobility of organic molecule chains as well as the low charge transfer and transportation efficiency in the composite materials, although the optic-electric conversion efficiency has already been improved up to 4% during these years. Focusing on this critical problem, a novel and suitable solar cell structure is to be fabricated in this program: a hybrid bulk-heterojunction structure with two continuous charge transportation channels composed of coupled organic nanowires (poly(3-hexylthiophene, P3HT) and inorganic core-shell nanotetrapods (CdSe/CuInSe2). Herein, we take the advantage of improving charge mobility through formation of naniwires by self-assembling organic molucule chains, also, improving charge transportation efficiency through formation of three dimentional network-like channels. A core-shell nantetrapod composed of CdSe/CuInSe2 is newly adopted as the electrons acceptor and collecting path while the P3HT nanowire is used as the electrons donor and holes transporting channel. An anvanced technique of preparing coupled composites is applied to fabricate the functional connection between P3HT nanowires and CdSe/CuInSe2 nanotetrapods, so that a bulk-heterojunction solar cell with two continous charge channels networks is creatively built up, enabling both a high charge transfer and collection efficiency. The performance optimization of solar cells is also to be researched. This program will solve the critical problem of small charge mobility as well as low transfer and transportation efficiency those existing in the composite bulk-heterojunction solar cells. Not only the composite materials with high performance together with their synthesis parameters will be given to improve the properties of hybrid solar cells, but also the correlated scientific fundamentals will be provided for the future commercialization of this kind of photovoltaic device.

虽然近几年的研究使得有机/无机复合体异质结太阳能电池的光电效率达到了4%，但是有机半导体高分子较小的电荷迁移率、复合体系较低的电荷转移与传输效率仍然是制约这类光伏器件发展的瓶颈与难点。本项目针对这一制约因素，利用半导体高分子自组装一维纳米结构可提高电荷迁移率的优点，借鉴三维网络状通道提升电荷传输效率的特点，采用P3HT纳米线作为电子给体与网络状空穴传输体，创新性采用CdSe/CuInSe2核壳结构纳米四角体作为电子受体与网络输运通道，并进一步利用先进的耦合复合技术将两种纳米结构单元进行功能组合，创造性构建兼备高效电荷转移效率和输运收集效率的双网络耦连体异质结太阳能电池，并进行器件的性能优化研究。本课题可解决目前复合体异质结太阳能电池中电荷迁移率和转移传输效率低的关键技术问题，不仅能为提升体异质结太阳能电池的性能提供优良的复合材料和工艺参数，而且可为这类光伏器件的未来产业化提供相关科学依据。

近几年，基于有机高分子半导体和无机纳米材料之间杂化体异质结构的太阳能电池备受关注。这两相材料的体相杂化有望获得优势互补和协同增强的效果。在该类器件中，有机高分子低的迁移率和无机纳米晶的单分散性影响的较低的电荷输运性质是制约器件光伏性能的主要因素。本项目针对这一制约因素，我们在本工作中制备了有机高分子纳米线和无机核壳结构的纳米四角体两种具有高效电荷传输能力的纳米单元，并采用化学键合将这两种纳米单元链接在一起，制备了有机高分子纳米线与无机核壳结构纳米四角体耦合杂化的异质结复合材料，并研制了杂化太阳能电池原型器件。研究结果表明，自组装获得的有机高分子纳米线具有良好的一维线状结构，结晶性能良好，电子迁移率得以提高；制备的核壳结构纳米四角体具有良好的单分散性和四角体形貌特征；两者的耦合结构形貌均匀，分散性好，适合做体异质结薄膜太阳能电池的光敏层；并且该类薄膜具有明显提高的激子分裂和电荷迁移性能。采用有机纳米线与无机纳米四角体耦合杂化的体异质结太阳能电池相比无耦合杂化的结构器件，在光伏效率上提高了80%，主要得益于光生电流密度的大幅度提高。本课题的研究在有机无机双纳米结构单元方面取得了创新性研究进展，可解决目前复合体异质结太阳能电池中电荷迁移率和转移传输效率低的关键技术问题，不仅能为提升体异质结太阳能电池的性能提供优良的复合材料和工艺参数，而且可为这类光伏器件的未来产业化提供相关科学依据。