采用旋涂的方法制备了(3,4-亚乙二氧基噻吩):聚(苯乙烯磺酸)(PEDOT:PSS)薄膜,结合液晶衬垫(LCS,liquid crystal spacer)对OLED进行光萃取,制备了结构为Glass/ITO/PEDOT:PSS/LCS/NPB(40nm)/Alq3(40nm)/LiF(1nm)/Al(100nm)的OLED以及其相应的对比器件。通过测量其电压、电流、亮度、色坐标和电致发光(EL)光谱等参数,研究了LCS对OLED发光性能的影响。结果表明,当引入LCS后,OLED在电压为11V时,最大电流效率达6.15cd/A,比不加LCS的器件提高了40%;且在电压从7V上升到12V的过程中,器件的色坐标仅从(0.31,0.57)变化到(0.31,0.56)。究其原因,LCS的引入可以提高透过率,破坏器件内部光的折射以及全反射条件,并使功能层形成褶皱结构,使更多的光子能够从器件内发射,也增大了电极的表面积,使电流密度增加,注入的能量提高。
The PEDOT:PSS film was prepared by using spin-coating method.Combined with the liquid crystal spacer(LCS)as light extraction material,the OLED device with the structure of glass/ITO/PEDOT:PSS/LCS/NPB(40nm)/Alq3(40nm)/LiF(1nm)/Al(100nm)and its corresponding contrast devices were prepared.By measuring the voltage,current,brightness,color coordinates,the electric light emission spectrum and other parameters,the influence of LCS on luminescence properties of the devices is studied.The maximum current efficiency of 6.15cd/A with a CIE chromaticity coordinate of(0.31,0.56)at the voltage of 11 Vis obtained in the device with the LCS,which is 40%higher than that of the OLED device without LCS.The CIE chromaticity coordinate changes only from(0.31,0.57)to(0.31,0.56)as the voltage increases from 7Vto 12 V.Reasons are that the introduction of LCS can improve transmittance and destroy the condition of light refraction and total reflection in the device.At the same time,the function layer can form into fold structure,which can make more photons emit from the device.The surface area of the electrode is increased,so the current density is increased,and the injected energy is improved.