将PEG(聚乙二醇)引入到ITO/MEH-PPV(聚(2-甲氧基,5(2'-乙基己氧基)-1,4-苯撑乙烯撑)/Al三明治器件中,实现了很好的电双稳性能。通过改变PEG的分子量、浓度以及退火温度等条件,对器件性能进行了优化。通过电流-电压(I-V)测试研究了不同器件的性能,结果表明,分子量为4 000的PEG,在30 mg/mL的浓度下,通过120℃退火制备的薄膜,其器件性能最优,电流开关比可以达到10^3以上。利用SEM测试研究了活性层的膜形貌,并结合电流-电压(I-V)曲线的线性拟合,分析了电荷在器件中的传输过程。研究发现,相分离产生的陷阱对电荷的俘获是该器件产生电双稳特性的主要原因。
Organic electrical bistable devices based on MEH-PPV (poly [ 2-methoxy-5-(20-ethyl- hexyloxy)-1,4-phenyl vinylene] ) and PEG[ poly( ethylene glycol)] bilayer films were demonstra- ted. The structure of the device is A1/MEH-PPV/PEG/ITO, and we optimize the device by chan- ging the molecular weight, concentration and annealing temperature of PEG film. The electrical cur- rent ON/OFF ratio of the optimized device is over 103 between the high-conducting state (ON state) and low-conducting state (OFF state). The device remains in the high resistance state below the threshold voltage of 2.5 V and the device resistance abruptly decreases due to the trap-controlled space charge limit current, leading to a high curve fitting indicate that the phase separation conductivity state. The SEM measurements and I-V induced electrical charge trapping plays an important role for the electrical bistable behavior of the devices.