基于MEH-PPV/ZnSe纳米复合器件的电致发光特性的研究

以巯基乙酸作为稳定剂在水相中制备了ZnSe纳米晶，用X射线粉末衍射(XRD)和X射线光电子能谱(XPS)对其进行了表征。用表面活性剂将ZnSe纳米晶从水相中转移到有机相中，使其与聚合物MEH-PPV复合作为发光层，制备了多层电致发光器件Glass/ITO/MEH-PPV∶ZnSe/BCP/Alq₃。对ZnSe纳米晶和MEH-PPV薄膜的光致发光谱及其吸收光谱的比较表明ZnSe纳米晶和MEH-PPV之间存在着能量传递，这是导致纳米复合薄膜的光致发光光谱和电致发光光谱存在差异的原因之一。文章对其在光激发和载流子注入条件下的不同发光机制进行了讨论。通过对器件的光电特性进行研究，发现ZnSe纳米晶发光的比例随着外加电压的增加而增加，而且器件的I-V特性基本上符合二极管的特性。

Investigation on Electroluminescence of MEH-PPV/ZnSe Nanocomposite Device

ZnSe nanocrystals were synthesized in aqueous solution by using mercapto-acetate acid as stabilizer.Products were characterized by X-ray diffraction patterns(XRD) and X-ray photoelectron spectra(XPS).A surfactant was used to transfer the nanocrystals from the aqueous solution to organic solvent,so that ZnSe and MEH-PPV could be mixed sufficiently and were used as an emitting layer in a multilayered electroluminescence device:Glass/ITO/MEH-PPV:ZnSe /BCP/Alq3/LiF/Al.A comparison between absorption spectra and photoluminescence spectra of ZnSe nanocrystals and MEH-PPV thin film exhibits an effective energy transfer from ZnSe nanocrystals to MEH-PPV,which is one reason for the existing difference between photoluminescence spectrum and electroluminescence spectrum of MEH-PPV:ZnSe nanocomposite film.The recombination mechanism of the nanocomposite film under photoexcitation and electric injection was discussed respectively.The authors investigated the photo-and electroluminescence properties of the device,and found that the EL intensity of ZnSe nanocrystals increased with the applied voltages.The I-V characteristic of this device is similar to that of a classic diode.