Design, Synthesis, And Optoelectronic Properties Of Conjugated Polymers With Deep-lying HOMO Levels

The conjugated polymers can be widely used for constructing flexible organic semiconductor devices by the solution processing method. A class of conjugated polymers with special photoelectric properties and chemical conformations can be synthisized by rationally designing the chemical structure of the polymers. A serious of medium bandgap D-A conjugated polymers with deep-lying HOMO energy level were designed and synthisized in this dissertation, which can be used as the donor material of the active layer of polymer solar cells(PSCs) with high Voc. Based on the 5,6-difluoro-2-heptylbenzo[d]thiazole unit and the flourene unit, a wide bandgap conjugated polymer with deep-lying HOMO enenrgy level were synthisized, which can be used as the emitting layer of organic light emitting dioes or the host material of the phosphorescent materials of PLED devices. We also designed and synthisized a water/alcohol soluble polyelectrolyte, which can be used to modify the cathode of polymer solar cells.In Chapter 2, a serious of carbazole-based medium bandgap conjugated polymers, PCDTBT12, PECz-BTBT6, PECz-BTBT8 and PECz-BTBT12, with deep-lying HOMO energy levels were synthisized. These polymers with good solubilty and solution processing performance, were used as the active layer of PSCs with high Voc. The power convert efficiency(PCE) of the PSCs based on these D-A conjugated polymers achieved to 6%. More over, these medium bandgap conjugated polymers are good candidates for the tandom solar cells, which can be used as the active layer of the subcell of tandom solar cells.In Chapter 3, the electron-withdrawing carboxylic acid octyl ester subsituens were introduced to the benzothiadiazole unit, and a new acceptor unit DEBT was synthisized. Based on the DEBT unit, three D-A conjugated polymers, PCz-DEBT, PECz-DEBT and PBDT-DEBT, were synthsized. The HOMO energy levels of these polymers were lowered because of the space steric effect and the electron-withdrawing effect of the substituents. So the Voc of the polymer devices based on PECz-DEB were as high as 1.05 V.In Chapter 4, a new unit of 5,6-difluoro-2-heptylbenzo[d]thiazole(ff BTz) were designed and synthisized, when copolymerizing with flourene unit, a polymer PF-ff BTz with deep-lying HOMO energy level was synthisized. A PLED device with a CIE(0.163, 0.056) were constructed, which was a standard blue emission. PF-ff BTz could also be used as the host material of FIrpic to construct high efficiency blue PLED devices. More β phase of polyfluorene can form, when the main chain of polyfluorene containing one percent ff BTz. Therefor, the electronluminescent properties can be improved.In Chapter 5, a water/alcohol soluble polyelectrolyte PF-ff BTz N with deep-lying HOMO energy level were synthisized. A high PCE of 8.74% was achieved when using PF-ff BTz N as the interface layer to modify cathode of the inverted solar cell device based on PTB7:PC71BM active layer. Then we studied the sability of PFN and PF-ff BTz N.