| The organic piezoelectric material P(VDF-TrFE)has been widely studied due to its excellent piezoelectricity.Since this material exhibits insulator properties,related research tends to combine P(VDF-TrFE)and organic semiconductors to prepare functional materials with both piezoelectric and semiconducting properties.It has broad application prospects in the fields of nanorobots,human-computer interaction,and energy harvesting.In this paper,P(VDF-TrFE)and organic semiconductor PFO phase-separated films are the main research objects,and transistors based on P(VDF-TrFE)/PFO phase-separated films were fabricated,and device arrays were realized on this basis.Ohmic and Schottky contacts were formed by choosing two different electrode materials.The compressive stress,polarization electric field,and temperature response of the piezoelectric electronic transistor were tested.The effective regulation of the potential barrier by piezoelectric charges was realized,and the reverse regulation of the bipolar plane was avoided.The flexibility of this organic material expandeds its application in flexible electronic devices.On this basis,a device array was fabricated and tested.Overall,an organic transistor was fabricated that avoided the buckling effect and reverse regulation of bipolar planes that existed in vertical transistors.The main research contents and conclusions are as follows:(1)P(VDF-TrFE)/PFO phase separation films were prepared.The effects of solution concentration,composition ratio,spin coating speed,annealing temperature and time on the film morphology,crystallinity and surface roughness were studied.The optimal conditions obtained in this experiment were: the total concentration of the solution was 30 mg/m L,the mass ratio of P(VDF-TrFE)to PFO was 10:1,the spin coating speed was 2000 r/min,the annealing temperature was 140 °C,and the time was 3 hours.The obtained P(VDFTrFE)/PFO phase-separated film had high crystallinity,uniform surface without pores,and its d33 piezoelectric coefficient was-16.65 pm/V.(2)The piezoelectric transistors based on P(VDF-TrFE)/PFO phase-separated films were prepared and their properties were studied.The response of the device was linearly related to the applied stress.The stress leaded to the reduction of the Schottky barrier at the Al/PFO interface and wss reflected in the on-current.For example,the on-current was 2.22 times higher under the stress condition of 800 k Pa than when no stress was applied.(3)The effect of operating temperature on piezoelectric transistors based on P(VDFTrFE)/PFO phase-separated films was systematically studied.For example,the on-state current changed by 138% when the operating temperature rised from 25°C to 65°C.(4)The effect of polarization direction on piezoelectric transistors based on P(VDFTrFE)/PFO phase-separated films was investigated.Under the same conditions,compared with the unpolarized state,the on-state current increased after forward polarization and decreased after reverse polarization.The compressive stress response of the device after polarization was nearly three times larger than that of the unpolarized device.The electric field polarization had a greater effect on the conduction characteristics of the device than the piezoelectric charge.(5)The response characteristics of piezoelectric transistor arrays based on P(VDFTrFE)/PFO phase-separated films were studied.3×3 device arrays were fabricated on rigid substrates and flexible substrates,and the pressure response tests were performed on the array devices.The results showed that the device array achieved in this paper could work independently without interfering with each other. |
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