The enhancement of hole injection layers is strongly important issue for obtaining high-efficient and low-driving-voltage Organic Light-Emitting Devices (OLEDs). In this paper, we presented a comprehensive electroluminescence (EL) study of phosphazene-based ionic liquids (PzILs) used as a hole transport layer in solution-processed OLEDs. Charge transfer properties of PzILs were investigated by doping in poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) at different ratios (0.1, 0.2, 0.5, 1.0, 2.0). Previously synthesized four types of PzILs (namely PzIL1, PzIL2, PzIL3, and PzIL4) were prepared in de-ionized water with 10 mg/ml concentration, mixed with PEDOT:PSS and examined for their charge transport characteristics on OLED device performance due to their ionic nature. The device with PzIL1 exhibited the best performance with luminance 4185 cd/m2 compared to other devices with and without PzILs. Further, Density Functional Theory (DFT) calculations and admittance spectroscopic analysis of OLEDs based on four types of PzILs were studied profoundly. Admittance spectroscopy has been used for revealing the carrier transport properties, mobility and the equivalent circuit modeling of the devices. Four types of PzILs OLEDs represented typical p-type transporting characteristics with moderate mobility up to 1.93 cm2/V.s.

中文翻译：

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有机发光二极管中磷腈基离子液体掺杂空穴传输层的载流子性能

空穴注入层的增强对于获得高效和低驱动电压的有机发光器件 (OLED) 是非常重要的问题。在本文中，我们对在溶液处理的 OLED 中用作空穴传输层的磷腈基离子液体 (PzIL) 进行了全面的电致发光 (EL) 研究。通过以不同的比例（0.1、0.2、0.5、1.0、2.0）掺杂聚（3,4-亚乙基二氧噻吩）聚苯乙烯磺酸盐（PEDOT：PSS）来研究 PzIL 的电荷转移特性。先前合成的四种类型的 PzIL（即 PzIL1、PzIL2、PzIL3 和 PzIL4）在去离子水中制备，浓度为 10 mg/ml，与 PEDOT:PSS 混合，并检查它们对 OLED 器件性能的电荷传输特性离子性质。与其他具有和不具有 PzIL 的器件相比，具有 PzIL1 的器件表现出最佳性能，亮度为 4185 cd/m2。此外，深入研究了基于四种 PzIL 的 OLED 的密度泛函理论 (DFT) 计算和导纳光谱分析。导纳光谱已被用于揭示载流子传输特性、迁移率和器件的等效电路建模。四种类型的 PzILs OLED 代表典型的 p 型传输特性，具有高达 1.93 cm2/Vs 的中等迁移率 导纳光谱已被用于揭示载流子传输特性、迁移率和器件的等效电路建模。四种类型的 PzILs OLED 代表典型的 p 型传输特性，具有高达 1.93 cm2/Vs 的中等迁移率 导纳光谱已被用于揭示载流子传输特性、迁移率和器件的等效电路建模。四种类型的 PzILs OLED 代表典型的 p 型传输特性，具有高达 1.93 cm2/Vs 的中等迁移率