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采用真空热蒸发的方法制备了V_2O_5薄膜,将其引入有机发光二极管(OLED)器件中用作空穴缓冲层,制备了以4,4’-N,N’-二咔唑基联苯(CBP)为主体材料,Ir(ppy)2acac为绿光磷光掺杂染料的OLED器件,结构为ITO/V_2O_5/NPB/TCTA/CBP∶Ir(ppy)2acac/BCP/Alq3/Li F/Al。研究了不同厚度的V_2O_5作为空穴缓冲层对绿色磷光OLED器件发光性能的影响。结果表明,当V_2O_5薄膜的厚度为30 nm时,器件的性能最佳,其最大电流效率和最大功率效率分别为54.36 cd/A和48.77 lm/W,比未加入缓冲层的常规器件均提高了34%。在驱动电压为11 V时,亮度可达到28 990 cd/m2,且在电压从5 V上升至10 V的过程中,对应的色坐标仅从(0.36,0.60)变化为(0.36,0.61),具有很高的稳定性。分析认为适当厚度的V_2O_5薄膜降低了发光层中空穴的浓度,提高了空穴和电子载流子的复合效率。
V_2O_5 thin films were prepared by vacuum thermal evaporation. The films were introduced into organic light-emitting diode (OLED) devices and used as hole-buffer layer. The films with 4,4’-N, ) As the host material, and the ITO (green) phosphorescent doping OLED device is Ir (ppy) 2acac. The structure is ITO / V2O5 / NPB / TCTA / CBP: Ir (ppy) 2acac / BCP / Alq3 / LiF / Al. The effects of V_2O_5 with different thickness as hole buffer layer on the luminescent properties of green phosphorescent OLED devices were studied. The results show that when the thickness of V_2O_5 thin film is 30 nm, the device performance is the best, the maximum current efficiency and maximum power efficiency are 54.36 cd / A and 48.77 lm / W respectively, which are higher than the conventional devices without buffer layer 34%. At a driving voltage of 11 V, the brightness can reach 28 990 cd / m2, and the corresponding color coordinate changes from (0.36, 0.60) to (0.36, 0.61) only when the voltage rises from 5 V to 10 V, Has a high stability. The V_2O_5 thin film with the proper thickness is analyzed to reduce the concentration of holes in the light-emitting layer and improve the recombination efficiency of holes and electron carriers.