[Tunneling electroluminescence of the ZnO nanorods/MEH-PPV heterojunction devices]

In the present paper, zinc oxide nanorods (ZnO-NRs) were synthesized by the hydrothermal method at lower temperature and the polymer poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) were used to fabricate an electroluminescent device based on the structure of "ITO/ZnO-seed/ZnO-NRs/MEH-PPV/Al". The measurement of current-voltage curve shows that it has a well rectifying characteristic. When a reverse bias exceeding 17 volts was applied to the ZnO-NRs/ MEH-PPV heterojunction, both emissions of ZnO and MEH-PPV were detected. And the intensity of near ultraviolet emission from ZnO is stronger than that of the orange-red emission belonging to MEH-PPV. It was also shown that the light power is gradually promoted with the increase in the reverse bias. Unfortunately, although carriers were injected into the heterojunction under the positive bias, we could not get any emissions. Its mechanism is attributed to the specificity of the organic inorganic hybrid heterojunction and the nanometer effects of ZnO-NRs. It is concluded that tunneling electroluminescence happens in this prepared device under the reverse bias.