LiF作为电子注入层对OLEDs器件性能的影响

制造了两种OLEDs器件,它们的结构分别为:ITO/NPB(50 nm)/Alq3(65 nm)/Mg:Ag(10:1)(100 nm)/Ag(50 nm)and ITO/NPB(50 nm)/Alq3(65 nm)/LiF(x)/Al(100 nm).结果发现,在同样电压下,与Mg:Ag/Ag电极相比,插入LiF层可以明显提高器件的电流.当LiF厚度为1 nm时,器件性能最好.以Mg:Ag/Ag合金作为电极时的器件的最大亮度为8 450 cd/m2,而插入LiF层的器件最大亮度可达到14 700 cd/m2.此外,器件的发光效率也得到了明显的提高,在7 V时达到了最大为3.117 cd/mA.同时,当LiF厚度大于1 nm或小于1 nm时,器件性能都将会下降.

Effect of LiF as Electron Injection Layer on OLEDs

Two kinds of OLEDs were fabricated.Their structures are respectively as follows:ITO/NPB(50 nm)/Alq3(65 nm)/Mg:Ag(10:1)(100,nm)Ag(50 nm)and ITO/NPB (50 nm)/Alq3(65 nm)/LiF(x)/Al(100 nm).The results show that it can ineresse the cur-rent of device obviously by inserting LiF layer compared with Mg:Ag/Ag electrode at the same voltage.When the thickness of LiF layer is 1 nm,the performance is the best.Its maxi-maI brightness can reach to 14 700 cd/m2,while that of Mg:Ag/Ag alloy electrode device is only 8 450 cd/m2.In addition,the luminous efficiency of the device mentioned above also has been ohviously improved,and has reached to the maximum 3.117 cd/mA under 7 V.Mean-wlhile,it is found that the performance will decrease along with the alteration of the thickness of LiF layer more or less than 1 nm.