Organic Electrical Bistable Devices Based On Poly[2-methoxy-5-(20-ethyl-hexyloxy)-1,4-phenylene Vinylene]Films

For the next generation electronics,the polymer optoelectronic devices have attracted more and more attention due to their unique advantages such as:simple fabrication process,low cost,large area and flexibility.This work has demonstrated the electrical bistable devices based on the commercial polymer MEH-PPV combined with PEG(polyethylene glycol)or Alq3.The electrical bistable performances and the principles of the devices are studied.The main contents are listed as follows:(1)PEG,a popular commercial dielectric polymer material,has been widely used in various optoelectronic devices due to its low price,stable performance,and green solvent.The devices with the structure of Al/MEH-PPV/PEG/ITO were fabricated.The effects of molecular weight,concentration and annealing temperature on the performance of PEG are studied.The maximum current ON/OFF ratio of the device can reach 103.In addition,the morphology of the active layer and the performance of the device were characterized by SEM test and I-V measurement respectively.Finally,the I-V curve fitting of the device implies that the bistable behavior of the MEH-PPV/PEG device is mainly attributed to the charge trapping at the interface of the active layer.(2)Alq3,a popular commercial small molecule organic material,has been widely used in organic OLEDs.Recently,Alq3 has been introduced into the organic bistable devices.However in the previous studies,the Alq3 active layers are usually fabricated by the traditional evaporation method,which limits the device application in the printing electronics.This work demonstrated a full solution spin coating method to fabricate the active layer(MEH-PPV/Alq3)of the electrical bistable devices.The I-V test results show that devices based on MEH-PPV/Alq3 active layer have a good electrical bistable property with the maximum switching ratio of 104 while the Alq3 device or MEH-PPV monolayer device has no electrical bistability.And the devices are quite stable in the air.Finally,based on the theoretical model of organic electronics and I-V curve fitting,the possible mechanism of the device is studied.