Molecular Design And Molecular Engineering Of Electret Based Transistor Memory

Organic field effect transistor(OFET)memories with electret is has a good application prospect due to non-destructive readout,simple fabrication processes and so on.But one of the reasons for the weak development is poor performance compared to other memory devices.So we design integrated molecule with charge trapping site and insulation polymer to improve memory performance based on the research basis of our group.Three poly(N-vinylcarbazole)(PVK)based polymer electrets were synthesized through Friedel-Crafts postfunctionalization.Ratio of hindrance groups to carbazole units of PVK were roughly calculated to be ca.1/6,1/13 and 1/14,respectively.With the increase of conjugation lengths of P1,P3,P2,these values of threshold voltages of positive exactly corresponded to conjugation lengths of them about 24.11,35.13,31.34 V.The result showed that the lengths of the modified conjugation groups were more important than the quantities of that for the electron capture.Afterwards,we design orthogonal experiment for charge trapping material/insulating polymer.Polymer including PVK,PS,PMMA,PPE and the trapping material containg SFDBAO,PO.The ratio of the small molecule to the polymer is 10%.The result show that PS has the best retention time and SFDBAO is a bettter trapping material.BrPS and SFDBAO was bond to be an integration molecule by coupling reaction,which include insulating layer and a charge trapping site in one molecule.The memory devices results showed exhibited memory window of-27.6 V which was increased by ca.68% with respect to-16 V of the composite of PS/SFDBAO.The result proved that molecular engineering of charge trapping site with insulating polymer is a promise strategy for the advance of transistor memory.