有机-无机复合薄膜电致发光器件中势垒对光电性能的影响

利用无机非晶SiO2与有机聚合物PPV复合制备了异质结器件,研究了不同层之间由于能级匹配而产生的势垒对整个器件的光电性能的影响。对于单层有机器件ITO/PPV/Al及双层有机无机复合器件ITO/PPV/SiO2/Al,空穴的注入取决于ITO/PPV界面的势垒,空穴是多数载流子,发光强度主要取决于电子的注入。单层器件电子的注入能力与PPV/Al界面的势垒有关;双层器件由于引进SiO2层,提高了电子的注入能力,其发光强度和发光效率较单层器件都有改善。对于3层有机-无机复合器件ITO/SiO2/PPV/SiO2/Al,在两个方向上电子注入的势垒不同,电子的注入能力有所差别,交流激发时,当Al电极为负(ITO为正)时,器件的最大瞬时发光强度是当ITO电极为负(Al为正)时最大瞬时发光强度的1.3倍。

Influence of the potential barrier in the organic-inorganic hybrid luminescent devices on the photoelectric properties

The influence of the potential barrier in the organic-inorganic hybrid luminescent devices(SiO2/PPV) on photoelectric properties is studied.For ITO/PPV/Al and ITO/PPV/SiO2/Al,the injection of the holes lies on the potential barrier on the interface of ITO/PPV.The holes are the majority carriers,so the intensity of the luminescence lies on the amount of the injected electrons.The ability of the injection of electrons in the single layer device is dependent on the potential barrier on the PPV/Al interface.The improvements of luminescence intensity and efficiency in double layer devices are due to the SiO2 layer which makes the ability of electron injection stronger.For the three-layer device ITO/SiO2/PPV/SiO2/Al,the potential barriers in two injection directions are different,and the abilities of the electron injection are different.The maximum of the instantaneous luminescence intensity,when the ITO is under positive voltage,is 1.3 times of that when the ITO contact is under negative voltage.