双空穴注入层对有机电致蓝光器件性能的改善

CuI/CuPc被采用作为有机电致蓝光CBP:BCzVBi器件 的双空穴注入层。采用双空穴注入层后使得CBP:BCzVBi蓝光器件的启亮电压降低至 3.4 V,较采用CuPc单空穴注入层的CBP:BCzVBi蓝光器件低0.4 V。在驱动电流20 mA/cm²的情况下,与单空穴注入层器件 相比,采用该双空穴注入层结构使得器件电流效率提升约19%,亮度 增加约17%,驱动电压降低0.9 V。采用Fowler -Nordheim (F-N)隧穿注入理论对器件空穴注入电流的影响因素进行了分析,发现双空穴 注入层形成的能级台阶可以有效地改善发光器件的空穴注入效率,进而起到改善器件发光电 流效率和降低驱动电压的目的。

Enhanced performance of blue organic light-emitting diodes by using a double ho le injection layer

Lowering down the driven voltage can b enefits to the luminous efficiency and the lifetime of the organic light-emitti ng device (OLED).To further decrease the hole injection barrier from the ITO ano de surface to the hole transport layer is a effective way to lower down the driv en voltage.In our work,a double hole injection layer (D-HIL) consisting of CuI/ CuPc was adopted into a CBP:BCzVBi blue emitter device to increase the hole inj ection efficiency.Comparing with the reference device with the single HIL layer of CuPc,the turn-on voltage of 3.4V was obtained in the D-HIL which lower 0.4V than the reference device,and the Current Efficiency (CE) was improved 19% at 20mA/cm2along with the driven-voltage lower down 0.9V than the reference de vice.The Fowler-Nordheim (F-N) tunneling theory was adopted to analyze the imp act of hole injection barrier on the hole injection electricity current density, it can be found that the hole injection electricity current density for the D-H IL device was improved via a stepped energy level which means a more facilitated hole injection efficiency,and hence the driven electricity current along with t he CE were improved.As a result,a clearly improvement in the CE and driven-volt age had been obtained in the D-HIL.