Donor-acceptor Polymer Memristor Based On Isoindigo And Its Performance Improvement

With the period of big data was coming,the development of traditional storage encountered bottleneck.Memristor is considered as one of the alternatives to traditional storage device because of its simple structure,fast response and easy integration.With film functional material developed from inorganic material to the organic material,researchers have found that organic materials have special memristive propertie.However,there are few studies on organic polymer memristor.In this paper,the organic polymers composed of iso-indigo,3,3-bis-decyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine?ProDOT-decyl₂?and thiophene were used as research objects.Al/polymer IPDT/ITO memristive devices were prepared by spin coating and thermal evaporation.The memristive properties were studied.The device performance is regulated by laser irradiation and structure changing.1.Donor-acceptor type semiconductor polymer?IPDT?was composed of iso-indigo,3,3-bis-decyl-3,4-dihydro-2Hthieno[3,4-b][1,4]dioxepine?ProDOT-decyl₂?and thiophene.The molar ratio of iso-indigo/thiophene/ProDOT-decyl₂ is x/1/1-x.The Al/IPDT/ITO organic electronic device was constructed and the memristive characteristics was studied.It was found that the device had a stable memory resistance characteristic.When x=0.5,the device show an 8/-7.5V On/Off voltage,high/low resistance ratio up to 10² and over 2000 times endurance cycles at room temperature.When x=0.25,the switching voltage decreased to 2.2/-1.6V and the maximum current decreased by 6 orders of magnitude.Even at x=0.2,the maximum current was still at the magnitude of nanoampere,the switching voltage was 1.9/-1.1V and the high/low resistance ratio exceeds 10³.The results show that the higher the ratio of donor units,the lower the switching voltage of the device.Finally,it was found that the memristive property of the device was due to the formation and fracture of electron channels inside the polymer materials.2.The effects of laser irradiation on the device were studied.The results showed that laser with 632 nm wavelength and 3mW power had a significant effect on the memory characteristics.After 60s of irradiation,the current direction of the drives was reversed.The On/Off voltage reduced to-2.2/1.3V,and the high-low resistance ratio increased to 10⁴.The current has dropped by an order of magnitude and the fluctuation was smaller,which effectively reduces the power consumption of the device.The number of stability cycle tests increased from 2000 to 3500 and improves the accuracy and stability of data reading.It was found that the device changed from a unipolar switching characteristic to a negative differential resistance characteristic after annealing at 120°C for 20 minutes.3.The property modulation of Al/IPDT/ITO memristive properties?the mole ratio of iso-indigo/thiophene/ProDOT-decyl₂ is 0.5/1/0.5?.By adding the electron transport layer?Graphene Oxide,GO?and the hole transport layer[N,N'-diphenyl-N,N'-bis?1-naphthyl??1,1'-biphenyl?-4,4'diamine,NPB]on the Al side,the ITO side and both electrodes simultaneously,it is found that the performance is improved sign after the addition of the graphene oxide layer to the Al and ITO electrode.The switching voltage of the device is decreased to 2.8/-1.8V,the switching resistance ratio was above 10³ and the maximum current of the device is reduced to 17?A.However,the memristive properties of the device are worse after the addition of the NPB hole transport layer,the switching voltage of the device becomes very high and the switching resistance ratio decreases.The results shows that the reason for the memristive phenomenon is the electron effect rather than the hole effect.