新型窄带隙聚合物太阳能电池材料的合成及性能研究

发布时间：2018-02-16 03:05

本文关键词： 有机太阳能电池共轭聚合物材料窄带隙聚合物拉/推电子基　出处：《华东理工大学》2014年博士论文　论文类型：学位论文

【摘要】：有机光伏技术为太阳能的有效利用提供了一条重要途径。凭借着其制造成本低廉、材料质量轻、加工性能好,易于携带等优势而备受关注。提高有机太阳能电池的光电转换效率是目前乃至未来的研究重点。设计和合成适合的窄带隙(LBG)的共轭聚合物是提高有机太阳能电池光电转化效率的核心。本论文主要围绕给体(D)-受体(A)型共轭聚合物材料的设计、合成以及光电性能研究,以期望获得高效的LBG共轭聚合物。主要内容如下： 1.设计合成了一系列基于环戊并二噻吩(CPDT)单元的D-A型LBG共轭聚合物,研究了氟原子及侧链对聚合物光电性质的影响。聚合物在可见及近红外区域内都表现出很强的吸光能力,能带间隙均小于1.5eV。由于氟原子的缺电子性质以及侧链的不同构型,导致聚合物在固体状态下表现出不同的排列方式,其中聚[2,6-(4,4-双(2-乙基己基)-4氢-环戊[2,1-b；3,4-b']二噻吩)-交-4,7(单氟-2,1,3-苯并噻二唑)]EH-FBT的π-π堆砌距离仅为是3.8A,空穴迁移率为0.014cm2V-1s"1。基于PCPDTFBT的异质结(BHJ)太阳能电池器件经过性能优化后光电转化率(PCE)达到6.6%,短路电流为14.3mA/cm2。将其进一步应用到双结(异质结)电池中,PCE高达8.2%。 2.设计合成了一个十一元共轭稠环化合物(IDTCPDT),该化合物表现出强的给电子能力,高的摩尔消光系数,好的刚性平面结构以及低的重组能。基于该给体单元,合成了窄带隙聚合物PIDTCPDT-DFBT,该聚合物拥有很强的吸光能力,很好的平面性,荧光寿命为1.52ns。理论计算得到的重组能只有3.2kcal/mol。基于该聚合物的场效应晶体管空穴传输能力可达2.4×10-2cm2V-1s-1。将该聚合物作为给体材料制作成为太阳能电池器件时,PCE为6.5%,短路电流为14.6mA/cm2,是目前已报道的基于阶梯型聚合物太阳能电池的最高值。 3.采用微波辅助Stille偶联设计并合成了三个基于吡咯并吡咯二酮(DPP)的二维共轭聚合物。由于DPP的较强缺电子特性,得到的三个聚合物都表现出极窄的能带间隙,分别为1.50,1.48和1.43eV,可以与太阳光谱很好的匹配。再者,DPP骨架出色的平面性以及其形成氢键的能力使得三个共聚物都具有较强的π-π堆砌能力。电化学测试表明,增加侧链的共轭长度可以有效的降低HOMO能级,提高聚合物电池的开路电压。值得注意的是活性层的形貌对激子的解离和扩散是非常重要的。当使用纯邻二氯苯作溶剂制备活性层时,聚合物与PC71BM之间形成尺寸较大的团聚体。当使用共混溶剂时(如氯仿和邻二氯苯)团聚现象消失,聚合物和(6,6)-苯基C71丁酸甲基酯(PC71BM)之间形成网状纳米纤维,极大的改善了聚合物与PC71BM之间的相互聚集,提高了激子的有效分离几率,器件的光电转化效率从原来的0.24%提高到4.47%。优化后的器件PCE最高达到了5.34%。 4.设计合成了苯并硒二唑衍生物单氟-2,1,3-苯并硒二唑(FBSe),增加了苯并硒二唑的吸电子能力并且降低了HOMO能级。并以FBSe为受体单元共聚得到聚合物PBDT-FBSe和PIDT-FBSe。两个聚合物都拥有较小的能带间隙分别只有1.60和1.58eV。其次,这两个聚合物具有良好的堆积作用,其薄膜紫外吸收较溶液吸收,发生了明显的红移。此外,PBDT-FBSe和PIDT-FBSe表现出较低的HOMO能级,这有利于在光伏器件中获得较高的开路电压。这两个聚合物的场效应晶体管空穴传输能力分别为1.1×10-4和3.0×10-3cm2V-1s-1。作为给体材料,BHJ太阳能电池的PCE分别达到5.00%和4.65%。 5.设计并合成了以氟代喹喔啉为受体单元的窄带隙聚合物PCPDT-DFPhQ, PCPDT-DFPhQ-M和PCPDT-DFPhQ-O,这些聚合物都具有很好的溶解性,能溶于大多数有机溶剂中。当引入烷氧基侧链时,聚合物PCPDT-DFPQ-O的HOMO能级显著升高。原子力显微镜结果表明较长的烷氧基侧链会引起聚合物空间位阻的增加,与PC71BM之间会形成尺寸较大的团聚体,影响激子的分离和扩散。因此,基于PCPDT-DFPhQ-O的太阳能电池器件,仅取得0.94%的PCE。其中短路电流只有2.52mA/cm2。相反,基于PCPDT-DFPhQ的电池获得最大PCE为5.30%,开路电压达到了0.83V,短路电流提升到12.05mA/cm2。 6.设计并合成了两个D-A1-D-A2型共轭聚合物PCPDT-DFBT-TPD和PCPDT-DFBT-DPP。这两个聚合物都拥有较小的能带间隙,较低的HOMO能级。此外PCPDT-DFBT-TPD和PCPDT-DFBT-DPP都能溶于绝大多数有机溶剂。而基于PCPDT-DFBT-TPD和PCPDT-DFBT-DPP的BHJ太阳能电池器件的PCE分别达到了3.15%以及3.11%。 7.系统总结了第二章至第七章的主要研究结果。
[Abstract]:Organic photovoltaic technology provides an important way for the effective use of solar energy. By virtue of its low manufacturing cost and material quality of light, good processing performance, easy to carry advantages and concern. Improve the photoelectric conversion efficiency of organic solar cells is the current and future research focus. The design and synthesis of suitable for narrow band gap (LBG the conjugated polymer) is the core to improve the photoelectric conversion efficiency of organic solar cells. This thesis mainly focuses on the donor (D) receptor (A) design of conjugated polymer materials, synthesis and optoelectronic properties of conjugated polymers, to obtain LBG with high efficiency. The main contents are as follows:
1. designed and synthesized a series based on cyclopent two thiophene (CPDT) type D-A LBG conjugated polymer unit, studied the effect of fluorine atom and the side chain of polymer. The polymer optical properties in the visible and near infrared region showed light absorption ability is very strong, the band gap of less than 1.5eV. due to the different configuration the lack of electronic properties of fluorine atom and the side chain, resulting polymers exhibit a different arrangement in the solid state, including poly [2,6- (4,4- bis (2- ethylhexyl) -4 hydrogen - cyclopent [2,1-b; 3,4-b'] two -4,7 (thiophene) - single fluorine -2,1,3- dibenzothiophene two triazole)]EH-FBT Pi Pi stack distance of only 3.8A, the hole mobilities for 0.014cm2V-1s 1. based on PCPDTFBT heterojunction (BHJ) solar cell device by photoelectric conversion rate optimization (PCE) reached 6.6%, the short circuit current is 14.3mA/cm2. be further applied to double junction (heterojunction) battery, PCE Up to 8.2%.
A conjugate fused eleven membered ring compounds were synthesized by the 2. design (IDTCPDT), the compound exhibits strong electron donating ability, high molar extinction coefficient, rigid flat structure and low energy. Based on the recombinant donor cell, low band gap polymer PIDTCPDT-DFBT was synthesized, the polymer has a light absorbing ability is very strong. The plane is very good, the fluorescence lifetime is 1.52ns. calculated the reorganization energy is only 3.2kcal/mol. of the polymer field effect transistor hole transport capacity of up to 2.4 * 10-2cm2V-1s-1. based on the polymer as donor materials to make a solar cell device, PCE is 6.5%, short circuit current is 14.6mA/cm2, is currently the highest value has been reported ladder type polymer solar cells based on.
3. microwave assisted Stille coupling was designed and synthesized based on three pyrrolo pyrrole ketone (DPP) two dimensional conjugated polymer. Due to the strong electron deficient character of DPP, the three polymer obtained showed a very narrow band gap, respectively 1.50,1.48 and 1.43eV, can match well with the solar spectrum the plane of the DPP skeleton. Moreover, excellent and its ability to form hydrogen bond makes three copolymers have strong tt-tt stacking ability. Electrochemical tests showed that the increased conjugation length of side chain can effectively reduce the HOMO level, improve the open circuit voltage of polymer battery. It is worth noting that the dissociation and diffusion morphology of active layer the exciton is very important. When using two pure ortho chlorobenzene as solvent and preparation of the active layer, the larger size of the aggregates formed between polymer and PC71BM. When using the blend solvent (such as chloroform and two adjacent benzene chloride) The reunion phenomenon disappeared, and the polymer (6,6) - phenyl C71 butyric acid methyl ester (PC71BM) formed between nano fiber mesh, greatly improve the aggregation between polymer and PC71BM, improve the effective separation probability of excitons, photoelectric conversion efficiency increased from 0.24% to 4.47%. after the optimization of device PCE reached the highest 5.34%.
4. design and synthesis of benzene derivatives and two fluorine selenium single -2,1,3- benzene and selenium (FBSe), two with increase of benzene and electron withdrawing ability of selenium was two and decreased HOMO level. And with FBSe as the acceptor unit of copolymerization of polymer PBDT-FBSe and PIDT-FBSe. two polymer have smaller band gap of only 1.60 and 1.58eV. second, the two polymer has good accumulation, the film with ultraviolet absorption solution absorption, obvious red shift occurred. In addition, PBDT-FBSe and PIDT-FBSe showed low HOMO energy levels, which is conducive to obtain a higher open circuit voltage in photovoltaic devices. The two polymer field effect transistor hole the transmission capacity was 1.1 * 10-4 and 3 * 10-3cm2V-1s-1. as donor materials, BHJ solar cells PCE were respectively 5% and 4.65%.
5. design and synthesis of low band gap polymer PCPDT-DFPhQ with fluorinated quinoxaline as receptor unit, PCPDT-DFPhQ-M and PCPDT-DFPhQ-O, these polymers have good solubility, soluble in most organic solvents. When introducing alkoxy side chain polymer PCPDT-DFPQ-O, HOMO level increased significantly. Atomic force microscopy showed that the alkoxy the base side chain longer increases polymer steric hindrance, and PC71BM will be formed between the larger aggregates, influence the separation and diffusion of excitons. Therefore, solar cell devices based on PCPDT-DFPhQ-O, only 0.94% PCE. the short-circuit current is only 2.52mA/cm2. on the contrary, PCPDT-DFPhQ battery based on the maximum PCE was 5.30%, reached 0.83V open circuit voltage, short circuit current up to 12.05mA/cm2.
6. design and synthesis of the band gap of two D-A1-D-A2 type conjugated polymer PCPDT-DFBT-TPD and PCPDT-DFBT-DPP. these two polymers have lower HOMO, lower level. The addition of PCPDT-DFBT-TPD and PCPDT-DFBT-DPP are soluble in most organic solvents. BHJ solar cell devices PCPDT-DFBT-TPD and PCPDT-DFBT-DPP based PCE respectively reached 3.15% and 3.11%.
The 7. system summarizes the main research results from the second chapters to the seventh.

【学位授予单位】：华东理工大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM914.4

【共引文献】