| The small organic semiconductors with solution processablity have been extensively studied due to their advantages of definite molecular structure,high air-stability,easy purification and high device performance,and have become one of the hot spots in the research of organic electronics,in particular for diketopyrrolopyrrole?DPP?-based semconductors.In this dissertation,we focus on synthesis of dimers of DPP to investigate the structure-property relationship of small molecule semiconductors.We explore their influence on the absorption,bandgap,crystal packing and device performance by introducing different alkyl side chains and halogen atoms to DPP.The research work includes the following two parts:1.Dimers(2DPP-C8H17 and 2DPP-C2C6)of dithiophene DPP with two different alkyl side chains were synthesized by the Stille coupling reaction and used for organic field effect transistors?OFETs?.The results showed that the compounds had better mobility and on/off ratios—the mobilities of dimers were 0.30 cm2 V-11 s-1and 0.93 cm2 V-11 s-1,respectively,and the on/off ratio as high as 105.2.Dimers(2DPP-Cl-C8H17 and 2DPP-Cl-C2C6)of chlorinated dithiophene DPP with two different alkyl side chains were synthesized by introduction of the electron-withdrawing substituent-Cl to the 3-position of thiophene of DPP.The introduction of chlorine atom changed the degree of conjugation and had great influence on the absorption,bandgap,crystal packing and device performance of the compound.The OFETs performance of the compound was reduced.The mobilities of dimers were 0.15 cm2 V-11 s-1 and 0.13 cm2 V-11 s-1,respectively,and the on/off ratios as high as 105. |
PDF Full Text Request