Design And Synthesis Of Novel Fused-ring Containing Conjugated Organic Semi-Conducting Materials And Their Opt-Electronic Properties

Fused-ring conjugated organic semi-conducting materials are used as one of the most important part of organic electronics. Design and synthesis of high performance fused-ring conjugated organic semi-conducting materials is of important significance for improving and adjusting the performances of the devices. In this thesis, from the perspective of the starting materials, a series of novel fused-ring conjugated organic semi-conducting materials were designed and synthesized, their optical performances and energy levels and electrochemical properties were studied and analyzed. According to their structure and performances, preliminary explorations were made on their applications in organic field-effect transistors and organic photovoltaic cells, the relationship between their structure and properties were discussed, and these can provide guidances and references for the design and synthesis of novel fused-ring conjugated organic semi-conducting materials. The main contents are as follows:In Chapter 2, by polymerization using the Suzuki coupling of 2,7-thienophenanthrene and 3,6-thienophenanthrene with 5,6-bis(octyloxy)-4,7-di(thiophen-2-yl)benzothiadiazole(DBT), two novel copolymers were synthesized, namely PTP36-DBT and PTP27-DBT. Their optical properties and electrochemical properties, and energy levels had been studied, indicating that the two polymeric materials have lower HOMO energy levels, the lower HOMO level in favor of a polymer solar cell device to obtain a higher open-circuit voltage(VOC). Two novel polymers PTP36-DBT and PTP27-DBT used for donor materials in bulk heterojunction solar cells, PC71 BM for acceptor material, the performances of the devices were investgated.In Chapter 3, a kind of novel fused-ring compounds containing three consecutive pyrrole rings structure, pyrrolo[3,2-b:4,5-b’]diindoles(PDIs), were synthesized. The 3,8-positions of PDIs with electron donating group thienyl, neutral group tolyl and electron withdrawing group cyano were functioned to extend the π-conjugated system, a total of six novel compounds namely 3,8-PDI-Tol-Th, 3,8-PDI-Tol-Ph, 3,8-PDI-Tol-CN, 3,8-PDI-C8-Th, 3,8-PDI-C8-Ph, 3,8-PDI-C8-CN were synthesized. The optical properties, electrochemical properties, and energy levels of PDI-Tol, 3,8-PDI-Tol-Th, 3,8-PDI-Tol-Ph, 3,8-PDI-Tol-CN, PDI-C8,3,8-PDIC8-Th, 3, 8-PDI-C8-Ph and 3,8-PDI-C8-CN were studied. The effects of different functional groups at the 3,8-positions on the optical, electrochemical properties and energy levels were analysized.In Chapter 4, novel fused-ring polymers containing three consecutive pyrrole ring structure using the Suzuki reaction, namely PPDI-Tol-C8 and PPDI-C8-C8, were synthesized. By changing the alkyl chain type of at the 5,6-positions to improve the solubility of PPDI-TolC8 and PPDI-C8-C8. The optical properties, electrochemical properties and the energy levels of PPDI-Tol-C8, PPDI-C8-C8, PPDI-Tol-EH and PPDI-C8-EH were studied. The novel polymers PPDI-Tol-EH and PPDI-C8-EH were also used as the active layer in OFETs.In Chapter 5, two novel D-A structure fused ring conjugated polymers PPDI-Tol-C8-DBT and PPDI-C8-C8-DBT were synthesized. Due to their poor solubility, by replacing the octyl chain at 5,6-positions by 2-ethylhexyl to improve the solubility of polymers. On this basis, the PDI units were copolymerized with different electron-deficient units and a series of novel fused-ring conjugated polymers with good solubility, namely PPDI-Tol-EH-DBT, PPDI-TolEH-BT, PPDI-Tol-EH-BT-F and PPDI-C8-EH-DBT, PPDI- C8-EH-BT and PPDI-C8-EH-BTF were synthesized. Optical properties and electrochemical properties and the energy levels of these polymers had been studied, the performances before and after changing the substituents at the 5,6-positions, as well as the 11-position substituent tolyl and octyl were analyzed. Eight of these fused ring conjugated polymer with D-A structure were studied when used in polymer photovoltaic cells as donor materials, from the perspective of substituents and copolymerized units, the relationship between photovoltaic performance parameters and copolymerized units and different substituents were analyzed.