Design,Synthesis And Semiconducting Properties Of B←N Coordinated Diketopyrrolopyrrole Based Polymers

It is important to develop conjugated polymers with high performance and reliability for flexible electronic devices.Compared with the units of electron donor,there are fewer units of electron acceptor,which limits the development of n-type and bipolar electron donor-acceptor conjugate polymers.In this thesis,combining B←N receptor unit with receptor unit of diketopyrrolopyrrole（DPP）,we design and synthesize new DPP receptor units containing single B←N and double B←N units（HBNDPP and DBNDPP）to obtaine a series of electron donor-accepter conjugate polymer molecular materials containing HBNDPP or DBNDPP.Their application in flexible organic field effect transistor（OFET）is also explored.The main research contents include the following two parts:1.We design and synthesize a new receptor molecule（HBNDPP）containing a single B←N coordination DPP unit,and the B←N coordination and DPP unit based conjugated polymers P1 and P2 are obtained.On the one hand,the LUMO energy levels of polymers are reduced by the ability of pulling electron of B←N and DPP units,and a single n-type electron transport is realized.On the other hand,by utilizing the asymmetric HBNDPP structure,the polymers exhibit several conformational isomers with flat torsional potential energy,thus presenting amorphous packing in the film state,which ensures good bending strain resistance.Therefore,the flexible OFET devices exhibit a single n-type charge characteristic and have good bending resistance and environmental stability.2.We design and synthesize a new receptor molecule（DBNDPP）containing double B←N coordination DPP units,obtaining the B←N coordination and DPP units based random polymers P3-0.17 and P4-0.09.On the one hand,HOMO and LUMO levels of polymers are regulated by the introduction of DBNDPP fused ring unit,so that the devices have characteristic of bipolar transmission.On the other hand,the random introduction of fused ring elements reduces the regularities of the polymers and improves the bending strain resistance.Therefore,the flexible OFET devices exhibit bipolar charge transfer characteristics with the highest hole and electron mobility of 0.9 and 0.57 cm²V^-1s^-1,and have good bending resistance and operational stability.