接触式双重体异质结宽光谱聚合物/小分子非富勒烯太阳能电池的研究

High efficiency, low cost and long service life are three key factors of large-scale industrialization of organic solar cell (OSC). Compared with the expensive polymer/fullerene materials, polymer/nonfullerene system especially polymer/small molecule nonfullerene system has gradually been in an international hot research of organic photovoltaic field with the advantages of low cost, high efficiency, easily-tunable energy band. Aiming at the key factors influencing device efficiency, such as heterojunction structures and light absorption properties, this project intends to design a kind of wide-spectral OSCs with directly-contacted double bulk heterojunction structure by combining polymer/small molecular fullerene materials with various bandgaps. By enhancing the optical absorption efficiency, broadening the absorption spectrum range and introducing the transition layer between two bulk heterojunctions to improve the carrier transport efficiency, this project would achieve wide spectrum and high efficiency OSC devices. The research contents mainly include four aspects: 1, developing directly-contacted double bulk heterojunction OSCs and construct dynamic models during deposition of active layers based on the stamp-transfer printing and in-situ-annealing spraying coating technologies; 2, controlling energy level diagrams of double heterojunctions based on the properties of active layers to improve the open circuit voltage of OSC, 3; broadening optical absorption wavelength range of double active layers according to the band-gap characteristics of organic functional layers to improve the device photocurrent; 4, controlling the morphology of the transition layer between the double heterojunction layers via solvent treatment to improve the fill-factor of OSC.

高效率、低成本、长寿命是实现有机太阳能电池（OSC）大规模产业化的三个关键因素。与成本高昂的聚合物/富勒烯材料体系相比，聚合物/非富勒烯尤其是聚合物/小分子非富勒烯体系具有成本低、效率高、能带易调控等优势，是当前国际有机光伏领域的研究热点。针对当前影响器件效率的异质结结构及光吸收特性的关键性科学问题，本项目拟采用不同带隙的聚合物/小分子非富勒烯材料体系，构建接触式双重体异质结的器件结构，增强光吸收效率和拓宽吸收光谱范围，引入过渡层以提升载流子输运效率，实现宽光谱、高效率的OSC器件，主要研究内容包括：1、基于粘贴转印和喷涂制膜技术研制接触式双异质结活性层，构建成膜动力学模型；2、基于活性层能级特性调控双异质结的能级结构，提升器件的开路电压；3、基于有机材料的光学带隙性质拓宽双异质结的吸收光谱范围，提高器件的短路电流；4、基于溶剂处理法调控双异质结中间过渡层的形貌，提升器件的填充因子。

本项目探究了不同带隙的聚合物/小分子非富勒烯材料体系，构建接触式双重体异质结的器件结构，增强光吸收效率和拓宽吸收光谱范围，引入过渡层以提升载流子输运效率，提出了具有柱状微纳表面的新型复合光学微腔结构，实现了宽光谱、高效率的有机太阳能电池（OSC）器件。研究内容主要包括：1、提高光吸收效率和拓宽吸收光谱范围，引入双重体异质结，提高载流子输运效率，提高了激子能量传递、载流子传递效率，建立了具有普遍适应性的双重体异质结器件的机理模型；2、针对单异质结光电器件存在光能利用率低和光生电压小的难题，提出了棱形分光光学模型和具有柱状微纳表面的新型复合光学微腔结构，可见-近红外范围的光场强度增加了30%，光电流提高至1.23倍；3、提出“结晶助剂法”增强了薄膜结晶性，实现了超快的光生电荷分离效应，提高了光电转换效率；4、研究了简单的醇溶剂和PBP添加剂处理方法提升非富勒烯有机太阳能电池的效率；5、研究了多受体的多元异质结有机太阳能电池的性能影响。该项目最终获得了国际先进转换效率17.5%的非富勒烯有机太阳能电池，共计发表论文SCI论文29篇，申请国家发明专利5项，在国际或国内重要学术会议上作特邀或邀请报告10次，培养硕士研究生3名。