基于三苯胺—苯并噻二唑不对称型小分子给体的设计合成及性质

发布时间：2018-04-20 12:50

本文选题：三苯胺 + 苯并噻二唑　；参考：《大连理工大学》2016年硕士论文

【摘要】：有机太阳能电池由于其显著的优点,比如成本低、质量轻以及机械灵活性引起了广泛的研究兴趣。目前,基于溶液可处理的有机小分子体异质结光伏器件的最大效率已超过10%。对于大多数有机小分子给体材料,按对称性其分子结构可分为对称型和不对称型。聚合物有机太阳能电池给体材料的单体多为D-A不对称结构,这类分子具有高效的分子内电荷转移,但是这类分子往往没有足够的光吸收能力。为了拓宽光谱吸收,进而提高光电转化效率,需要利用多功能性基团修饰来设计新型分子。本论文报道了BTO和BTF两个系列共8个D-A1-A2型不对称结构的有机小分子给体材料。在这些分子中,采用三苯胺作给电单元(D),含烷氧链的苯并噻二唑(BTO)和含双氟的苯并噻二唑(BTF)分别作吸电单元(A1),给电单元和吸电单元之间分别以苯基、苯乙烯基、苯乙炔基和2-苯基丙烯氰基作桥键构成基本的D-π-A1结构。为了改善材料的光谱吸收能力,引入另一个吸电单元(A2)对氰基苯基延长分子结构,延伸出8个D-A1-A2型分子。我们对BTO和BTF系列材料进行高斯理论计算、紫外-可见光谱吸收和循环伏安测试以及制作成溶液可处理的体异质结器件,探究苯并噻二唑核上不同的取代基及不同的桥键对材料光物理及光电性能的影响。测试结果表明：1)两个系列材料由于引入苯并噻二唑强吸电基使其具有较低的HOMO能级,均获得较高的开路电压,达到0.9V以上。2)苯并噻二唑核上引入双氟使BTF系列材料的HOMO能级进一步降低,与BTO系列材料相比,其对应材料的开路电压略有提高。3)苯并噻二唑核上引入烷氧链使BTO系列材料在氯仿溶液中具有良好的溶解性因而具有良好的成膜性,有效地改善了短路电流和填充因子。4)桥键主要影响材料的HOMO能级,对LUMO能级影响较小,以2-苯基丙烯氰基为桥键的材料具有较低的HOMO能级,因而基于材料TPACNBTFCN为给体的器件获得了1.01V的开路电压：基于TPACNBTOCN为给体的器件经溶剂蒸汽退火处理后同时具有高开路电压和高短路电流,表现出最优的光电转化效3.03％,Jsc=9.48 mA.cm-2,Voc=1.00V,FF=0.32。
[Abstract]:Organic solar cells have attracted extensive research interest due to their significant advantages, such as low cost, light mass and mechanical flexibility. At present, the maximum efficiency of organic small molecular heterojunction photovoltaic devices based on solution treatment has exceeded 10. For most organic small molecular donor materials, their molecular structures can be divided into symmetric and asymmetric types according to symmetry. Most of the monomers of polymer organic solar cell donors are D-A asymmetric. These molecules have highly efficient intramolecular charge transfer, but these molecules often do not have sufficient optical absorption capacity. In order to broaden the spectral absorption and improve the photoelectric conversion efficiency, multifunctional group modification is needed to design novel molecules. In this paper, two series of BTO and BTF organic small molecular donors with D-A1-A2 asymmetric structure are reported. Among these molecules, trianiline was used as the feed unit, benzothiadiazolium containing alkoxy chain (BTOO) and difluorinated benzothiadiazolium (BTF) as the absorbent unit, respectively, and phenyl and styrene groups were used between the feeding unit and the absorbent unit, respectively. The basic structure of D- 蟺-A _ 1 is formed by using phenylacetylene and 2-phenylpropene cyanide as bridge bonds. In order to improve the spectral absorption ability of the material, another electric-absorbent unit (A2) was introduced to prolong the molecular structure of cyanophenyl, and eight D-A1-A2 type molecules were extended. We have made theoretical calculations of BTO and BTF series, UV-Vis spectral absorption and cyclic voltammetry, and fabricated bulk heterojunction devices that can be treated in solution. The effects of different substituents and bridge bonds on the photophysical and optoelectronic properties of benzothiadiazole were investigated. The test results show that the two series of materials have higher open circuit voltage due to the introduction of a strong absorbent group of benzothiadiazole, which has a lower HOMO energy level. The introduction of difluorine into the nucleus of benzo-thiadiazole (> 0.9V) further reduced the HOMO energy level of BTF series, compared with that of BTO series materials. The open-circuit voltage of the corresponding material increased slightly. 3) the introduction of alkoxy chain to the nucleation of benzothiadiazole made the BTO series materials have good solubility in chloroform solution and thus good film formation. The short circuit current and filling factor. 4) bridge bond mainly affect the HOMO energy level of the material, and have little effect on the LUMO energy level. The material with 2-phenylpropene cyanide as bridge bond has lower HOMO energy level. Therefore, the device based on material TPACNBTFCN as donor obtains an open circuit voltage of 1.01V: the device based on TPACNBTOCN has high open circuit voltage and high short circuit current after solvent steam annealing, which shows the optimum photoelectric conversion efficiency of 3.03g / s 9.48mA.cm-2Vocn 1.00V / FF0.32.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O626

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