基于二噻吩并咔唑与苯并噻二唑的 D-A 型共轭聚合物的合成与表征
文献类型：学位论文
| 作者 | 荣梓清 |
| 学位类别 | 硕士 |
| 答辩日期 | 2015-05 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 中国科学院长春应用化学研究所 |
| 导师 | 耿延候 |
| 关键词 | 由于给体片段（D）和受体片段（A）间的电荷转移 D-A型共轭高分子通常具有较小的光学带隙 且分子偶极矩较大 分子间相互作用较强 利于获得高的载流子迁移率 因此 D-A型共轭聚合物是有机太阳能电池材料领域的研究热点。另一方面 稠环分子由于具有刚性平面的构型 重组能小等优点而被广泛引入D-A型共轭聚合物体系中。因此 本文以二噻吩并[2 3-b:7 6-b]咔唑（C1）和二噻吩并[3 2-b:6 7-b]咔唑（C2）两个稠环单元作为给体片段 苯并噻二唑（BT）单元作为受体片段合成了一系列D-A型共轭聚合物 并且对它们的光物理性质 电化学性质 载流子传输和光伏特性进行了系统研究 主要成果和创新点如下： （1）合成了基于二噻吩并咔唑和烷氧基取代的BT单元的两个聚合物P(BT-C1)和P(BT-C2) 它们均是无定形聚合物。 尽管P(BT-C1)和P(BT-C2)在分子结构上只有硫原子位置不同的差别 但两者在长波长和短波长范围表现出完全相反的相对吸收强度。 通过理论模拟可以发现 两个聚合物骨架构象完全不同 P(BT-C1)的骨架较为弯曲 而P(BT-C2)的骨架线性较好。因此 基于P(BT-C2)的有机薄膜晶体管（OTFT）的迁移率较高 达到5.4×10-3 cm2V-1s-1 而P(BT-C1)的OTFT迁移率较低 为1.9×10-3 cm2V-1s-1。 P(BT-C2)的HOMO能级比P(BT-C1)深0.2 eV左右 因此 基于P(BT-C2)的体异质结有机太阳能电池（OSC）器件的开路电压（Voc）明显高于P(BT-C1) 而P(BT-C1)与PC71BM共混薄膜相分离更加明显 导致P(BT-C1)的OSC器件的短路电流密度（Jsc）和填充因子（FF）较高 两个聚合物的能量转换效率（PCE）相差不多 均在5%左右。 （2）以C2为给体单元 BT和二氟代BT为受体单元 合成了两个共轭聚合物P(C6BT-C2)和P(C6BT2F-C2)。与P(BT-C2)相比 P(C6BT-C2)具有较高的热稳定性 HOMO能级升高 光谱红移。在BT单元上引入F原子后 聚合物的HOMO能级由P(C6BT-C2)的-5.00 eV降低到P(C6BT2F-C2)的-5.20 eV 同时帯隙变窄。 理论模拟发现两者的分子平面性比P(BT-C2)有很大改善 但分子骨架构象较为弯曲。基于P(C6BT-C2)与P(C6BT2F-C2)的OTFT器件在150 oC退火后载流子迁移率分别为4.8×10-3 和4.9×10-3 cm2V-1s-1 。由于与PC71BM共混薄膜的相分离不明显 基于P(C6BT-C2)与P(C6BT2F-C2)的OSC器件的Jsc和FF较低 PCE均小于2%。 |
| 英文摘要 | Because of charge transfer between donor (D) and acceptor (A) segments, D-A conjugated polymers generally have narrower band gaps, larger molecular dipole moments, and stronger intermolecular interaction, which are favorable for achieving high charge-carrier mobility. Thus, the D-A conjugated polymers is a research focus in the field of organic solar cell materials. On the other hand, fused aromatics are characterized with rigid and coplanar configurations and small reorganization energy, thereby are widely used in the design and synthesis of D-A conjugated polymers. Therefore, in this thesis, a series of D-A conjugated polymers were synthesized using dithieno[2,3-b:7,6-b]carbazole (C1) or dithieno[3,2-b:6,7-b]carbazole (C2) as donor unit and benzothiadiazole (BT) as acceptor unit, and their photophysical, electrochemical, carrier transporting and photovoltaic properties were studied in detail. The main achievements are as follows: 1. Two polymers P(BT-C1) and P(BT-C2) based on dithienocarbazole and alkoxy substituted benzothiadiazole were synthesized, and they are both amorphous. Although their molecular structures are almost the same except the positions of S atoms in dithienocarbazole units, they exhibited reverse relative absorption intensity in long and short wavelength regions. As indicated by theoretical simulation, these two polymers display distinct backbone conformation. The backbone of P(BT-C1) was curved, while that of P(BT-C2) was almost linear. Consequently, the carrier mobility of OTFT device based on P(BT-C2) was 5.4×10-3 cm2V-1s-1, higher than 1.9×10-3 cm2V-1s-1 of OTFT device based on P(BT-C1). The HOMO energy level of P(BT-C2) was 0.2 eV deeper than that of P(BT-C1), thus, the open-circuit voltage (Voc) of the OSC device based on P(BT-C2) was obviously higher. However, the short-circuit current density (Jsc) and fill factor (FF) of the OSC device based on P(BT-C1) were higher because of more obvious phase separation of its blend film with PC71BM. As a result, PCEs of the OSC devices based on two polymers were almost the same, which were both around 5%. 2. Two polymers P(C6BT-C2) and P(C6BT2F-C2) using C2 as donor and benzothiadiazole or fluoro-benzothiadiazole as acceptor were synthesized. Compared to P(BT-C2), P(C6BT-C2) exhibited higher thermal stability, deeper HOMO energy level and red-shifted absorption spectrum. After introducing F atoms into BT unit, the HOMO energy level of P(C6BT2F-C2) decreased to -5.20 eV from -5.00 eV of P(C6BT-C2). Meanwhile, the band gap was also reduced slightly. Theoretical simulation indicated that two polymers displayed more planar but more curved backbones, as compared to P(BT-C2). Upon thermal annealing at 150 oC, OTFT devices based on P(C6BT-C2) and P(C6BT2F-C2) exhibited mobilities of 4.8×10-3 and 4.9×10-3 cm2V-1s-1, respectively. Probably due to poor phase separation between polymers and PC71BM in the blend films, Jsc and FF values of the OSC devices based on P(C6BT-C2) and P(C6BT2F-C2) were relatively low and the PCEs of both polymers were below 2%. |
| 语种 | 中文 |
| 公开日期 | 2016-05-03 |
| 源URL | [http://ir.ciac.jl.cn/handle/322003/64457]  |
| 专题 | 长春应用化学研究所_长春应用化学研究所知识产出_学位论文 |
| 推荐引用方式 GB/T 7714 | 荣梓清. 基于二噻吩并咔唑与苯并噻二唑的 D-A 型共轭聚合物的合成与表征[D]. 中国科学院长春应用化学研究所. 中国科学院研究生院. 2015. |
入库方式： OAI收割
来源：长春应用化学研究所
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