基于苯并二噻吩和吡咯并吡咯二酮共聚物的有机太阳能电池给体材料光伏性质理论研究  

Theoretical Investigation on Photovoltaic Properties of BDT and DPP Copolymer as a Promising Organic Solar Cell

作　　者：赵蔡斌[1] 王占领[2] 周科[1] 葛红光[1] 张强[1] 靳玲侠[1] 王文亮[3] 尹世伟[3] 

机构地区：[1]陕西理工学院化学与环境科学学院,汉中723000 [2]陕西理工学院机械工程学院,汉中723000 [3]陕西省大分子科学重点实验室陕西师范大学化学化工学院,西安710062

出　　处：《化学学报》2016年第3期251-258,共8页Acta Chimica Sinica

基　　金：国家自然科学基金(No.21373132);陕西理工学院博士科研启动基金(Nos.SLGKYQD2-13;SLGKYQD2-10;SLGQD14-10)资助~~

摘　　要：设计和合成结构新颖的聚合物太阳能电池给体材料是有机电子学的热点研究领域.首先利用二噻吩取代的苯并二噻吩(DBDT)作为富电子结构单元,吡咯并吡咯二酮(DPP)作为缺电子单元构筑了一种新的聚合物太阳能电池电子给体材料(PDBDTDPP),然后以[6,6]-苯基-C61-丁酸甲酯(PC61BM)作为电子受体,借助密度泛函理论(DFT)方法结合不相干的Marcus-Hush电荷传输模型,系统研究了PC61BM-DBDTDPPn=1,2,3,∞体系的分子结构、电子性质、光吸收性质、电荷转移的内重组能和外重组能、激子结合能、电荷传输积分、给体-受体界面上激子分离和电荷复合速率等性质,并利用线性回归方法分析了聚合物重复单元与其光伏性质的关系.结果表明,该聚合物具有较好的平面结构,低的最高占据分子轨道(HOMO)能级,在紫外-可见区具有宽且强的光学吸收、较大的激子束缚能(1.365 e V),小的激子分离内重组能(0.152 e V)和电荷复合内重组能(0.314 e V).在给体-受体界面上,激子分离速率高达1.073×1014 s-1,而电荷复合速率仅为1.797×108 s-1.相比较而言,激子分离速率比电荷复合速率高约6个数量级,表明在给体-受体界面上,光生激子具有很高的分离效率.总之,研究证明PDBDTDPP是一个非常有前途的聚合物太阳能电池给体材料,值得实验上进一步合成及器件化研究.理论研究不仅有助于更深入理解有机化合物结构与其光学、电子性质之间的关系,还可以为合理设计聚合物太阳能电池给体材料提供有价值的参考.Designing and synthesizing novel polymer electron-donor materials of polymer-based solar cells（PSCs） with the high photovoltaic performance is an important and hot research field of organic electronics. In the current work, taking the 4,8-di（thiophen-2-yl）benzo[1,2-b：4,5-b＇]dithiophene（DBDT） as the electron-rich unit and the 3,6-di（thiophen-2-yl）pyrrolo[3, 4-c]pyrrole-1,4（2H,5H）-dione（DPP） as the electron-deficient one, a new donor material（PDBDTDPP） of PSCs has been designed. Then, with the [6,6]-phenyl-C61-butyric acid methyl ester（PC61BM） as an electron acceptor, the geometries, electronic properties, optical absorption properties, intramolecular and intermolecular reorganization energies, exciton binding energies, charge transfer integrals, and the rates of exciton dissociation and charge recombination for PC61BMDBDTDPPn=1,2,3,∞ systems have been theoretically investigated by means of density functional theory（DFT） calculations coupled with the incoherent Marcus-Hush charge transfer model and some extensive multidimensional visualization techniques. In addition, the linear regression analysis has been done to explore the relationship between the above properties and the repeating unit. Calculated results show that the designed donor polymer possesses a good planar geometry, the low-lying the highest occupied molecular orbital（HOMO） level, strong and wide optical absorption in ultraviolet-visible band, large exciton binding energy（1.365 e V）, and the relatively small intramolecular reorganization energies companying with the exciton dissociation（0.152 e V） and charge recombination（0.314 e V） processes. Furthermore, our theoretical study also reveals that in the donor-acceptor surface, the exciton dissociation rate is as high as 1.073×10^14 s^-1, while the charge recombination rate is only 1.797×10^8 s^-1. The former is as six orders of magnitude large as the latter, which denotes that there is quite high exciton dissociation efficiency in the studied

关 键 词：聚合物太阳能电池 苯并二噻吩 吡咯并吡咯二酮 激子分离 电荷复合 

分 类 号：O631.3[理学—高分子化学] TM914.4[理学—化学]