Synthesis,Properties Of Conjugated Polymers Based On Diketopyrrolopyridazine

Pyrrolo[3,4-d]pyridazine-5,7-dione has highly electron deficient as strong acceptor unit, it can effectively reduce LUMO levels of the conjugated polymers, it also has a symmetric and coplanar structure at the same time. The conjugated polymer based on pyrrolo[3,4-d]pyridazine-5,7-dione unit can be efficient charge separation and pyrrolo[3,4-d]pyridazine-5,7-dione unit introduced in alkyl chain can bring good solubility. Therefore, we designed and synthesized a series of conjugated polymers based on pyrrolo[3,4-d]pyridazine-5,7-dione (PPD) unit, and study on their properties. The main research work is as follows:Two new conjugated polymers P1 and P2 with pyrrolo[3,4-d]pyridazine-5,7-dione unit as acceptor and benzodithiophene (alkoxy side chains and alkylthienyl were introduced in benzodithiophene respectively) as donor were designed and synthesized (Chapter 2). Compared with polymer PBDTPh-BT, polymer P1 and P2 exhibited much wider absorptions, much smaller bandgaps and lower LUMO levels. The BHJ solar cells based on the two polymers as the electron donors and PC71BM as the electron acceptor achieved PCE of 2.71% and 3.66% for polymers P1 and P2, respectively.We synthesized the acceptor-π-acceptor (A1-π-A2) conjugated polymer based on 6-alkyl pyrrolo[3,4-d]pyridazine-5,7-dione (PPD) unit and diketopyrrolopyrrole (DPP) unit. Based on the OTFTs device of the PPPD-DPP shows ambipolar transfer characteristic in a vacuum, the highest electron and hole mobility respectively are 0.03 cm2/V.s and 0.05 cm2/V.s, but the device shows obvious p-type transfer characteristic in air, the hole mobility reaches up to 0.12 cm2/V.s.