利用低温水热法生长的ZnO纳米棒(ZnO--NRs),和P型有机半导体材料聚[2-甲氧基-5-(2-乙基己氧基)-1,4-苯撑乙烯撑](MEH-PPV)复合制备了结构为“ITO/ZnO晶种/ZnO--NRs/MEH-PPV/A1”的发光器件。测试结果发现,该器件具有非常好的二极管整流特性。对ZnO~NRs/MEH-PPV异质结施加超过17V的反向偏压时,可同时获得两种半导体材料的发光,且ZnO近紫外光(380nm)发射强度远大于MEH-PPV的红橙光强度,发光功率随着反向偏压的增加迅速增强,然而施加正向偏压时未探测到发光。该器件的发光机理不同于其他文献报道的正偏压发光,而属于反偏压发光器件,其发光机理归因于有机无机复合异质结的界面特殊性和zno-NRs的纳米尺寸效应,反偏压下器件实现的是载流子隧穿发光,而正偏压时载流子以表面态的无辐射复合及漏电流方式消耗。
In the present paper, zinc oxide nanorods (ZnO-NRs) were synthesized by the hydrothermal method at lower tempera ture and the polymer poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) were used to fabricate an elec troluminescent device based on the structure of "ITO/ZnO-seed/ZnO-NRs/MEH-PPV/AI'. 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 hy brid heterojunction and the nanometer effects of ZnO-NRs. It is concluded that tunneling electroluminescence happens in this pre pared device under the reverse bias.