Synthesis Of Acceptor-Acceptor Type Conjugated Polymers And Their Applications On Organic Optoelectronic Devices

Since the 21st century,polymer organic semiconductor materials have received extensive attention due to their characteristics of thin,flexible,low cost,easy processing,and large-scale industrial production.However,most researchers currently focus on conjugated polymers that absorb in the visible region rather than the near-infrared region.Therefore,by introducing the strong electron-withdrawing unit pyridinethiadiazole?PT?,based on the strong electron-withdrawing unit diketopyrrolopyrrole unit?DPP?,we developed a new narrow band-gap conjugated polymer with high mobility Materials to improve the performance of the polymer material in organic photovoltaics?OPV?and Organic field-effect transistors?OFET?.The work of this thesis is to design,synthesize D-A1-A2 conjugated polymers and A1-A2 type dual receptor conjugated polymers based on DPP and PT units,and prepare them OPV and OFET devices respectively.The main research contents and results are as follows:1.We design and synthesize a new type D-A1-A2 conjugated polymer Material PBDT-DPP-PT by introducing a strong electron-withdrawing unit PT into polymer PBDT-DPP,and explore the relationship between its structure and performance.Previously,there have been reports of conjugated polymers of BDT and BT units,but the band gap is wide and they cannot absorb sunlight well.Because the PT unit has one more N atom on the heterocycle than the BT unit,the PT has a stronger electron-withdrawing ability.At the same time,the PT unit also has better molecular coplanarity,which can improve the carrier transport ability of polymer materials Therefore,we replaced the BT unit with the PT unit to redesign the molecular structure and successfully synthesized the polymers PBDT-DPP and PBDT-DPP-PT.After cyclic voltammetry testing,it is found that the polymer PBDT-DPP-PT introduced into the PT unit has a lower LUMO energy level than the polymer PBDT-DPP,which is conducive to improving the carrier transport capacity and reducing the energy band-gap down.The ultraviolet-visible absorption spectrum also shows a red shift,which is beneficial to improve the absorption range of the device for sunlight.2.In order to obtain high-performance n-type polymer materials,this article uses DPP as the skeleton structure and introduces the PT unit to synthesis polymers.Since the N atoms in the PT unit are randomly arranged in the region of the polymer,the conventional polycondensation method can only obtain the region random Type?polymer,so we obtained a new type A1-A2 conjugated polymer type II polymer with unidirectional arrangement of N atoms in the local area through the optimization of the synthetic route.The HOMO/LUMO energy levels of type?polymer and type?polymer are-5.42 eV/-3.62 eV and-5.43 eV/-3.68 eV respectively.It can be found that both have a lower LUMO energy level,and at the same time,a region-regulated polymer has a lower LUMO energy level and a narrower band gap than a region-random polymer.We prepared type?polymer and type?polymer as OFET devices.After testing,their hole mobility were 0.1 cm² V^-1 s^-1 and0.13 cm² V^-1 s^-1,respectively.The results show that our newly synthesized A1-A2 polymer has great potential in OFET.At the same time,the design idea of regionally regular polymers has also been proven to be effective in improving intermolecular packing and preparing high mobility organic semiconductor materials Strategy.