标题: | 以吡咯并吡咯二酮作为连接基之线型及超分枝聚噻吩衍生物之合成及光电性质研究 Synthesis and Opto-electrical Investigation of Linear and Hyperbranched Polythiophene Derivatives Containing Diketopyrrolopyrroles as Linking Groups |
作者: | 谢家豪 Hsieh, Chia-Hao 杨胜雄 Yang, Sheng-Hsiung 光电系统研究所 |
关键字: | 吡咯并吡咯二酮;超分枝;聚噻吩;Diketopyrrolopyrrole;Hyperbranched;Polythiophene |
公开日期: | 2013 |
摘要: | 本研究之目的在合成出含吡咯并吡咯二酮作为连接基之线型及超分枝聚噻吩衍生物,并探讨其热性质、光学性质、电化学及光伏特性。本研究同时制备聚(3-己基噻吩)以作为对照之用。所有高分子皆以通用格林纳金属催化途径合成,其数量平均分子量经测定介于2.14–4.03×104 g/mol之间,而重量平均分子量则介于3.92–9.98×104 g/mol之间,分子量分布则为1.81–2.85。使用核磁共振光谱仪分析所有高分子之立体规则度皆达96%以上。利用热重分析仪及示差扫描卡计探讨高分子热性质,所有高分子于300 oC呈现第一阶段热损失温度;此外含有吡咯并吡咯二酮之高分子经高温加热后,相较于聚(3-己基噻吩)其热重损失量较小,显示确实增强材料的热稳定性。所合成之高分子于薄膜态的紫外–可见光吸收光谱皆与聚(3-己基噻吩)大致相符。而含有吡咯并吡咯二酮之高分子之萤光放射产生衰减,说明在这些材料中激子不易经由再结合而放光;易言之,应用于太阳能元件时载子有更多机会传递至两端电极以增加电流值。利用循环伏安计量法分析电化学特性,得知引入吡咯并吡咯二酮团基能降低材料之最高已填满分子轨域及最低未填满分子轨域。以高分子作为主动层制作单电洞元件,并利用空间电荷限制电流公式计算得知直链型聚噻吩系列以P1-50的迁移率最高,达到2.1–2.2×10-4 cm2/Vs,超分枝聚噻吩系列则以P2-10的迁移率最高,达到1.7–1.8×10-4 cm2/Vs。最后,将所有高分子用于制作反结构太阳能元件之主动层,结构为ITO/ZnO nanorods/P2-PF6/Polymer:PC61BM/PEDOT/WO3/Au,其中ZnO nanorods作为电子传输层,P2-PF6作为润湿层,PEDOT作为电洞传输层,以及WO3作为电洞萃取层。经测量得知直链型聚噻吩系列作为主动层之元件其开路电压为0.55–0.58 V、短路电流为8.62–16.21 mA/cm2、填充因子为37–41%及光电转换效率值为1.73–3.74%。超分枝聚噻吩系列作为主动层之元件其开路电压、短路电流、填充因子及光电转换效率则分别为0.55–0.58 V、9.49–11.87 mA/cm2、36–38%及2.01–2.49%。以上结果显示含吡咯并吡咯二酮之直链型高分子相较于超分枝高分子作为高分子太阳能元件之发展潜力较高。 The goal of this research is to synthesize the linear and hyperbranched polythiophene derivatives containing diketopyrrolopyrrole as linking groups, and to investigate the thermal, optical, electrochemical, and photovoltaic properties of those derivatives. Poly(3-hexylthiophene) (P3HT) was also synthesized for comparison in this study. All polymers were synthesized via the Universal Grignard metathesis. The number-average molecular weights of polymers were measured to be in the range of 2.14–4.03×104 g/mol, while their weight-average molecular weights were in the range of 3.92–9.98×104 g/mol, with polydispersity index of 1.81–2.85. The regioregularity of all polymers were analyzed by nuclear magnetic resonance spectrometer to be higher than 96%. The thermal characteristics of polymers were investigated by differential scanning calorimeter and thermogravimetric analyzer, showing a first-stage weight loss at about 300 oC; in addition, polymers containing diketopyrrolopyrrole groups possess less weight loss than P3HT after heating, indicative of enhanced thermal stabilities. The UV-vis absorption spectra of the synthesize polymers are similar to that of P3HT in film state. Polymers containing diketopyrrolopyrrole groups show distinct attenuation in fluorensencent emission, indicating that excitons are not easy to recombine to emit light in those materials; in other words, there are more opportunities for carriers to transport to both electrodes to increase current. The electrochemical properties of polymers were analyzed by cyclic voltammetry, revealing that introduction of diketopyrrolopyrrole groups may result in decreasing HOMO and LUMO levels of polymers. All polymers were used as active layers for fabrication of hole only devices and applied space-charge-limited-current (SCLC) model to extract the charge carrier mobility. P1-50 exhibited a highest hole mobility of 2.1–2.2 × 10−4 cm2/Vs of linear polythiophene series; P2-10 exhibited a highest hole mobility of 1.7–1.8 × 10−4 cm2/Vs of hyperbranched polythiophene series. Finally, all polymers were used as active layers for fabrication of inverted solar devices with the configuration of ITO/ZnO nanorods/P2-PF6/polymer:PCBM/PEDOT/WO3/Au, using ZnO nanorods as electron transporting layer, P2-PF6 as wetting layer, PEDOT as hole transporting layer, and WO3 as hole extraction layer. The devices based on linear polythiophene series as active layers were measured to show the open-circuit voltage (VOC) of 0.55–0.58 V, the short-circuit current (JSC) of 8.62–16.21 mA/cm2, the fill factor (FF) of 37–41%, and the power conversion efficiency (PCE) of 1.73–3.74%. The devices based on hyperbranched polythiophene series as active layers showed VOC, JSC, FF, and PCE values of 0.55–0.58 V, 9.49–11.87 mA/cm2, 36–38%, and 2.01–2.49%, respectively. The above results demonstrate that the linear polymers containing diketopyrrolopyrrole showed better potential use in polymer solar devices than hyberbranched ones. |
URI: | http://140.113.39.130/cdrfb3/record/nctu/#GT070158004 http://hdl.handle.net/11536/76066 |
显示于类别: | Thesis |