基于新型碳基量子点增强聚合物太阳能电池性能及其机制的研究

Polymer solar cells (PSCs) have developed rapidly during the past decade because of their various advantages, such as low-cost processing and suitability to industrial manufacturing of large-area and flexible devices. However, the power conversion efficiency (PCE) is poor due to the inadequate absorption of sunlight and the mismatch of the energy levels. Smart materials based on carbon quantum dots offer a promising prospect for high performance PSCs. In this project, carbon quantum dots are used to improve the absorption of sunlight, the property of the interlayer, the generation and separation of excitons, the transfer and extraction of carriers of PSCs by manipulating the optical properties, photo-induced electron transfer and the dipole polarity. The enhanced mechanism of PSCs by carbon quantum dots is illustrated by studies of the micro-structure of carbon quantum dots, the chain structure of conjugated polymers, the degree of donor/accepter separations. This work may get a deep insight into the coupling and the transfer mechanism of exciton, phonon and photon in the carbon quantum dots-PSCs system, providing a scientific basis and theoretical guidance for the design and fabrication of high-performance polymer solar cells.

聚合物太阳能电池由于其制备成本低、适用于大面积及柔性器件的制备的优点而发展迅速，针对聚合物太阳能电池的光利用率低、器件内能级匹配欠佳等导致的器件效率较低的问题，本项目拟设计并制备光电性能易调控的碳基量子点材料。通过调控碳基量子点的光学特性、光诱导电子转移特性、偶极性等，优化器件对光的利用率、界面层特性、激子产生及分离、载流子运输及收集，从而提高聚合物太阳能电池的光伏性能。在研究碳基量子点微结构、共轭聚合物分子链结构、给体-受体相分离程度等对光谱特征影响的基础上，探索碳基量子点聚合物光伏器件体系激子、声子以及光子等基本量子之间的耦合和转化机制，阐明碳基量子点提高聚合物太阳能电池性能的机理，为设计新型高效的聚合物太阳能电池提供依据。

本项目旨在制备光电性能易调控的碳基量子点界面材料用于有机/聚合物太阳电池，优化器件对光的利用率、界面层特性、激子产生及分离、载流子运输及收集，从而提高有机/聚合物太阳电池的光伏性能。首先，通过一锅法微波合成功能化的环境友好碳基量子点，引入极性基团氨基或是碱金属元素，优化碳量子点的光电特性及偶极性等。将制备的碳基量子点用于改善传统界面材料的界面修饰性能或单独作为界面层，均可提高太阳电池器件对光的利用率、优化能级匹配度、增加电荷提取效率、降低电荷复合损失，最终提高器件效率。当碳基量子点用于改善传统界面材料性能时，器件效率提升了20%；当碳基量子点单独作为界面层用于太阳电池，器件效率提升了96%。其次，通过研究极性界面材料分子取向、共轭聚合物分子链结构、给体-受体相分离程度等对光谱特征的影响，探索了极性界面材料的取向对功函数、电荷的提取及传输的影响，分子链结构、相分离程度对激子耦合和分离的影响，最终阐明了增强界面材料偶极强度对提高有机/聚合物太阳电池性能的机理。本项目的研究为设计新型高效的光伏器件界面层提供了有力支持，并拓宽了碳基量子点的应用领域。