[Electroluminescence property of MEH-PPV/ZnO nano-crystal structure]

A new structure with II-VI nano-crystal ZnO film as the electron transport layer and MEH-PPV as the hole transport layer and emitting layer was fabricated. The new structure's brightness and efficiency were improved markedly compared with that of the single MEH-PPV layer structure. And a new peak at 620 nm was found in the ITO/MEH-PPV/ZnO/Al structure's electroluminescence spectrum, which should resulted from ZnO layer. In addition, the turning-on voltage of the two-layer structure decreased from 9 V of the single layer structure to 4 V. From the I-V curve, the authors concluded that the emitting area was around the interface of MEH-PPV/ZnO and the combination area could shift with changing the voltage.