摘要
采用含氟异靛蓝单元(fIID)和硼氮配位键桥联噻吩联噻唑单元(BNTT)交替共聚制备了高分子电子受体,聚(N,N’-双(2-庚基十二烷基)-含氟异靛蓝-co-双苯基硼氮配位键桥联噻吩联噻唑)(P-BN-fIID)。采用理论计算、紫外-可见吸收光谱、循环伏安测试以及掠入射X射线衍射等研究了材料的结构与性质的关系,并制备了全高分子太阳能电池器件,研究了其光伏性能。结果表明:与基于异靛蓝单元(IID)的高分子聚(N,N’-双(2-己基辛基)-异靛蓝-co-双苯基硼氮配位键桥联噻吩联噻唑)(P-BN-IID)相比较,含有氟原子的P-BN-fIID的最低未占据分子轨道能级(ELUMO)降低了0.1 eV,吸收光谱红移了25 nm;同时,P-BN-fIID的结晶性明显提高,具有相对紧密的堆积结构和较高的电子迁移率。采用经典的高分子给体聚(2-烷硫基噻吩取代的二维共轭苯并二噻吩-co-噻吩桥联苯并三氮唑)(J61)与P-BN-fIID共混组装的全高分子太阳能电池器件,其能量转化效率(PCE)为2.83%。说明氟原子可以有效调节高分子受体的光电性质和结晶性,高分子受体的结晶行为明显影响全高分子太阳能电池的器件性能。
All-polymer solar cells(all-PSCs), which utilize conjugated polymers as both electron donor and electron acceptor, have received great attention for the great advantages of tunability of energy levels of the polymer acceptors,improved solar light absorption and enhanced mechanical/thermal stability. The investigations on the relationships between chemical structures and properties of polymer electron acceptors are very important for the design of efficient polymer acceptor materials and the development of all-PSCs. A polymer acceptor, P-BN-fIID, was synthesized by alternating copolymerization of boron-nitrogen coordination bond bridged thiophene-thiazole unit(BNTT) and fluorinated isoindigo unit(fIID). The relationships between the chemical structure and the photophysical, electrochemical properties as well as the molecular stacking behavior were investigated. According to the electrochemical data, P-BN-fIID showed the lowest unoccupied molecular orbital and the highest occupied molecular orbital energy levels(ELUMO/EHOMO) of-3.90/-5.86 eV. In the absorption spectrum, it exhibited the absorption peak at 720 nm. Compared with the reference polymer P-BN-IID based on isoindigo unit(IID) and BNTT unit, P-BN-fIID had a lower ELUMO by 0.1 eV and a red-shifted absorption by 25 nm.Moreover, P-BN-fIID displayed improved crystallinity with the dense molecular packing, thus leading to the enhanced electron mobility of 3.54 × 10-5 cm2/(V·s). All-PSCs device based on the blend of P-BN-fIID and a conventional polymer donor J61 exhibited a power conversion efficiency of 2.83%. Results suggest that fluorine atom can effectively tune the electronic properties and crystallinity of polymer acceptors and thus improve the photovoltaic performance.
作者
赵汝艳
窦传冬
刘俊
王利祥
ZHAO Ruyan;DOU Chuandong;LIU Jun;WANG Lixiang(Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China)
出处
《功能高分子学报》
CAS
CSCD
北大核心
2019年第5期601-609,共9页
Journal of Functional Polymers
基金
中国科学院青年创新促进会(2017265)
国家自然科学基金(21822507,21625403)
关键词
全高分子太阳能电池
高分子受体
硼氮配位键
氟原子
结晶性
all-polymer solar cells
polymer acceptors
boron-nitrogen coordination bond
fluorine stom
crystallinity