摘要
采用Stille缩聚,合成了3个异靛蓝并[7,6-g]异靛蓝(DIID)和乙烯单元交替排列的共轭聚合物P0F、P2F和P4F,三者在DIID单元中分别含0、2和4个氟原子(F).3个聚合物均具有良好的平面性,前线分子轨道几乎在整个共轭骨架上离域.它们均具有宽的吸收光谱,吸收范围在400~1000 nm,光学带隙约为1.25 eV;随着氟原子数目的增加,聚合物的最高占有分子轨道(HOMO)和最低空分子轨道(LUMO)能级依次下降0.1~0.2 eV.以这3个聚合物作为活性层,制备了顶栅-底接触型有机场效应晶体管器件,随着氟原子数目的增加,聚合物的传输性质由双极传输变为n型传输.P0F和P2F是双极传输型聚合物,空穴迁移率(μ_h)分别达到0.11和0.30 cm^2 V^(-1) s^(-1),电子迁移率(me)分别达到0.22和1.19 cm^2 V^(-1) s^(-1).P4F是n型聚合物,me达到0.18 cm^2 V^(-1) s^(-1).
Three alternating conjugated polymers of isoindigo[7,6-g]isoindigo（DIID） and vinylene, i.e., P0F, P2F and P4F, in which DIID units contain 0, 2 and 4 fluorine（F） atoms, respectively, were synthesized via Stille polycondensation. The number-average molecular weights（Mn） were 3.94 × 10^4, 4.45× 10^4 and 1.93× 10^4 for P0F, P2F and P4F, respectively. All these three polymers are largely planar and their frontier molecular orbitals are well-delocalized along conjugated backbones as revealed by density functional theory（DFT） calculation. Their 5 wt% weight loss temperatures are above 360 ℃. They all have very broad absorption spectra in the range of 400 - 1000 nm and their optical band-gaps are ca. 1.25 eV. With an increase ofF atoms, both the highest occupied molecular orbital（HOMO） and the lowest unoccupied molecular orbital（LUMO） energy levels decreased, from-5.26 and-3.57 eV for P0F to-5.48 and-3.68 eV for P2F, and further to-5.62 and-3.82 eV for P4 F. Thin films of the polymers were characterized by X-ray diffraction and atomic force microscopy（AFM）. All these polymers formed ordered structure in their films with conjugated backbone adopting an edge-on arrangement. The portion of the ordered structure in the films increased from P0F to P4F, along with the increase in F-atoms in DIID unit. Top-gate and bottom-contact（TGBC） organic field-effect transistors（OFETs） of the polymers were fabricated with poly（methylmethacrylate） as dielectric via solution spin casting with o-dichlorobenzene. The device performance was measured under ambient conditions. With increasing the number ofF atoms, the transfer behaviour of the devices based on the polymers changed from ambipolar to unipolar n-type. P0F and P2F were ambipolar polymers. Their hole mobility was 0.11 and 0.30 cm^2 V^-1 s^-1, respectively, and the electron mobility was 0.22 and 1.19 cm^2 V^-1 s^-1, respectively. P4F was a typical unipolar n-type semiconductor and its electron mobility was up to 0.18 cm^2 V^-1 s^-1. The re
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2017年第7期1141-1149,共9页
Acta Polymerica Sinica
基金
国家重点研发计划(项目号2016YFB0401100)
国家自然科学基金(基金号51333006)资助项目
