A-A型有机太阳能电池给体材料的合成及光伏性能研究

发布时间：2018-05-05 18:27

本文选题：A-A型共轭材料 + 活性层　；参考：《北京交通大学》2017年硕士论文

【摘要】：有机太阳能电池(OPVs)因其材料易得、合成成本低、柔韧性好以及可溶剂化大面积制备等特点,具有巨大的应用潜力,成为了近年来国内外的研究热点。其能量转换效率得到了一定程度的提高,但想要将其产业化还有很长的路要走。有机太阳能电池性能主要取决于活性层的光电转换过程,因此活性层材料的开发一直是有机太阳能电池领域的研究重点和突破点。本论文以有机太阳能电池给体材料为研究对象,提出了一种Acceptor-Acceptor(A-A)型共轭给体材料的设计方法,将两个缺电子单元引入到材料的共轭主链,合成出了一系列A-A型聚合物、小分子给体材料并对其光伏性能进行了系统研究,为有机太阳电池给体材料的设计提供了新的思路。主要研究结果如下:1.设计并合成出一种基于两个吸电子单元diketopyrrolopyrrole(DPP)和pentacycliclactam(PCL)的A-A型窄带隙聚合物PDPP2TPCL。研究表明两个吸电子单元的引入能够有效拓宽聚合物的吸收光谱,降低聚合物的能级。有机场效应晶体管(OFET)测试的结果表明聚合物具有0.81 cm2 V-1 s-1的高空穴迁移率。以其作为给体、富勒烯衍生物[6,6]-4-苯基-C61-丁酸甲酯(PC61BM)作为受体制备有机太阳电池得到了 4.7%的光电能量转换效率(PCE)和0.65 eV的能量损失。2.以PDPP2TPCL为基础,通过引入甲基对其结构进行微调,合成出了两个新的A-A型共轭聚合物。研究发现甲基噻吩的引入能够适当提升聚合物的能级,使聚合物的吸收产生轻微的蓝移,但其在OFET中仍具有相近的空穴迁移率。将其作为给体材料应用到有机太阳能电池中,结果显示,含甲基的聚合物的器件活性层具有更好的相分离尺寸,器件短路电流得到了显著提升,PCE从4.2%提升到了6.1%。研究结果表明,通过分子结构的设计与细微调控能够有效改变材料的能级和微观形貌,从而提升材料的光电性能。3.沿用A-A型共轭给体材料的设计策略,设计并合成出一个基于上述强吸电子单元DPP和弱吸电子单元PCL的窄带隙小分子给体材料PCLDPP。研究发现A-A型结构的设计能够使共轭小分子具有较短共轭主链的同时得到较窄的能量带隙和较宽的吸收光谱。以PCLDPP作为给体、PC61BM作为受体制成的OPV器件得到了 4.8%的PCE,而以非富勒烯小分子做为受体的电池器件得到了 2.4%和3.5%的PCE,表明以多个缺电子基团为骨架设计合成的共轭小分子在有机太阳能电池中具有一定的应用潜力。通过对器件性能与形貌的研究表明,载流子迁移率不匹配以及相分离尺寸过大等缺陷降低太阳能电池的光电流,从而降低器件的能量转换效率,为设计高效有机太阳能电池提供了参考。
[Abstract]:Organic solar cell (OPVs) has become a research hotspot in recent years because of its advantages of easy availability, low synthesis cost, good flexibility and solvability and large area preparation. Its energy conversion efficiency has been improved to a certain extent, but there is still a long way to go to industrialize it. The performance of organic solar cells mainly depends on the photoelectric conversion process of the active layer, so the development of the active layer materials has always been the focus and breakthrough point in the field of organic solar cells. In this paper, an Acceptor-Acceptor A-A) conjugate donor material is proposed. Two electron-deficient elements are introduced into the conjugate main chain of the material and a series of A-A polymers are synthesized. The photovoltaic properties of small molecular donor materials are systematically studied, which provides a new idea for the design of organic solar cell donor materials. The main results are as follows: 1. An A-A narrow band gap polymer PDPP2TPCL was designed and synthesized based on two electron absorption units, diketopyrrolopyrrole (DPP) and pentacycliclactamet (PCL). It is shown that the introduction of two electron absorption units can effectively broaden the absorption spectra of the polymer and reduce the energy level of the polymer. The results of field effect transistor (FET) measurements show that the polymer has a high hole mobility of 0.81 cm2 V-1 s-1. Using the fullerene derivative [6n6] -4-phenyl--C61-butyrate (PC61BM) as the acceptor to prepare organic solar cells, the photovoltaic energy conversion efficiency (PCEE) and the energy loss of 0.65 EV were obtained. Based on PDPP2TPCL, two new A-A conjugated polymers were synthesized by introducing methyl to fine-tune their structures. It is found that the introduction of methylthiophene can increase the energy level of the polymer properly and cause a slight blue shift in the absorption of the polymer, but it still has similar hole mobility in OFET. The results show that the active layer of the polymer containing methyl has a better phase separation size, and the short circuit current of the device has been significantly increased from 4.2% to 6.1%. The results show that the energy level and micro-morphology of the material can be changed effectively by the design and fine regulation of molecular structure, and thus the photoelectric properties of the material can be improved by .3. Using the design strategy of A-A conjugate donor material, a narrow band gap small molecule donor material PCLDPs based on the strong electron absorption unit (DPP) and the weak electron absorption unit (PCL) was designed and synthesized. It is found that the design of A-A structure can make the conjugated small molecule have shorter conjugate main chain and narrow energy band gap and wider absorption spectrum. The OPV devices using PCLDPP as donor PC61BM as acceptor obtained 4.8% PCEs, while those with non-fullerene small molecules as acceptor got 2.4% and 3.5% PCEs, indicating that many electron deficient groups were used as the skeleton to design and synthesize the PCEs. Small yoke molecules have some potential applications in organic solar cells. The study on the performance and morphology of the device shows that the defects such as mismatch of carrier mobility and excessive phase separation size reduce the photocurrent of the solar cell and thus reduce the energy conversion efficiency of the device. It provides a reference for the design of efficient organic solar cells.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM914.4

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