| Selenophene derivatives have tight molecular arrangement and strong intermolecular charge transfer due to intermolecular Se···Se interactions,which facilitates carrier transfer.Selenophene derivatives have been gradually applied in the field of organic photoelectric materials.In this thesis,six kinds of selenophene-based organic semiconductor materials were designed and synthesized by changing the combination mode of two selenophene rings and the isomerization of octyl in the capping group which starting from selenophene.The organic thin-films were prepared by vacuum deposition and solution-processed method.And to explore the relationship between structure and performance by characterizing the performance of bottom gate top contact type organic field effect transistor devices.The research work in the thesis is composed of four parts:1)Synthesis of six kinds of selenophene-based organic semiconductor materials:Through formylation,metal catalytic C-H activation coupling,Mcmurry reaction,bromination,TMS protection,bromine dance reaction and iodinated,Sonogashira Coupling and selenium cyclization,three kinds of dialdehyde derivatives of diselenophene with different combination modes were synthesiszed:?E?-5,5'-?ethene-1,2-diyl?bis?selenophene-2-carbaldehyde?,2,2'-biselenophene-5,5'-dicarbaldehyde,selenopheno[3,2-b]selenophene-2,5-dicarbaldehyde.Following the Wittig reaction of dialdehyde derivatives of diselenophene and the ylide,six kinds of selenophene-based organic semiconductor materials were synthesized:1,2-bis?5-?4-octylstyryl?selenophen-2-yl?ethene?1?,5,5'-bis?4-octylstyryl?-2,2'-biselenophene?2?,2,5-bis?4-octylstyryl?selenopheno[3,2-b]selenophene?3?,1,2-bis?5-?4-?2-ethylhexyl?styryl?selenophen-2-yl?ethene?4?,5,5'-bis?4-?2-ethylhexyl?styryl?-2,2'-biselenophene?5?,2,5-bis?4-?2-ethylhexyl?styryl?selenopheno[3,2-b]selenophene?6?from selenophene,and the total yields are41.8%,39.7%,23.0%,24.3%,30.5%,and 20.2%,respectively.The structures of orresponding intermediate and target compounds have been characterized.2)Photophysical,electrochemical behaviors and thermal stability of six kinds of selenophene-based organic semiconductor materials:The maximum absorption spectra exhibit blue shift with the change of combination mode from double bond to single bond and to fusion.The optical band gaps of the selenophene-based organic semiconductor materials are 2.40 eV for 1 and 4,2.46 eV for 2 and 5,2.67 eV for 3 and 6,respectively,which are calculated from absorption spectra.The HOMO levels are-5.29,-5.51,-5.49,-5.14,-5.21 and-5.12 eV for 1-6,respectively,which are obtained from cyclic voltammetry curve.All of them have higher thermal stability,and the decomposition temperatures are all above 330 oC.3)The OFETs performance of 1,2,3 by vacuum deposition method:The characteristic of thin films based on SiO2/Si and OTS-SiO2/Si substrates different substrate temperature were investigated by atomic force microscopy?AFM?and X-ray diffraction?XRD?.The results show that all the films have good crystallinity.The modification of substrates with OTS are beneficial to the growth of the film and crystallinity.Compound 3 exhibits strong?-?stacking on the OTS-SiO2/Si substrate,and shows good semiconductor performance.The hole mobility up to 0.38 cm2 v-1 s-1 for 3,when the substrate was modified with OTS and the substrate temperature was 25 oC.And the hole mobilities up to 0.02 and 0.11cm2 v-1 s-11 for 1 and 2,respectively,when the substrate was modified with OTS and the substrate temperature was 60 oC.The results indicate that 3 with fused two selenophene rings exhibit better semiconductor properties4)The OFETs performance of 1-6 by solution-processed method:The characteristic of thin films which based on SiO2/Si and OTS-SiO2/Si substrates were investigated by AFM and XRD.The result shows that compounds 1-6 all exhibit good crystallinity,but they are easy to aggregate and difficult to form continuous films.Characterization results of bottom gate top contact organic field effect transistor devices with compounds 1-6 as active layer show that compounds 1,2,3 exhibit good performance on the OTS-SiO2/Si substrates,and the hole mobility up to 3.86×10-3,8.49×10-3 and 0.047 cm2 V-11 s-1,respectively.The compounds 4 and 6 exhibit good performance on the SiO2/Si substrates with hole mobility of 4.53×10-33 and8.4×10-44 cm2 V-1 s-1.However,the aggregation of compound 5 is very serious,which caused large contact resistance between film and substrate,and no transistor performance is detected. |
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