The excited-state energy transfer widely exists in mixed-material systems and devices. The modulation of an electric field on the energy transfer in photoluminescence has been demonstrated. However, to date, no studies on the electric-field modulation of the excited-state energy transfer in organic optoelectronic devices have been reported. Herein, we investigate the effect of an electric field on the energy transfer in the poly(N-vinylcarbazole) (PVK) thin films doped with iridium(III)[bis(4,6-difluorophenyl)pyridinato-N,C^2′]-tetrakis(1-pyrazolyl)borate (Fir6) and 5,6,11,12-tetraphenylnaphthacene (rubrene) (PVK:Fir6:rubrene) and the corresponding light-emitting diodes. Combined with the Onsager model describing electric-field enhanced exciton dissociation, we find that the electric field increases the rate of Dexter energy transfer from Fir6 to rubrene in the films and the diodes. The voltage-dependent color shift in the PVK:Fir6:rubrene light-emitting diodes can be explained by the electric-field enhanced Dexter energy transfer from Fir6 to rubrene. Our findings are important for the control of energy transfer process in organic optoelectronic devices by an electric field for desirable applications.

中文翻译：

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磷光材料和荧光材料共掺杂聚合物发光二极管中的电场调制能量转移

激发态能量转移广泛存在于混合材料系统和器件中。电场对光致发光能量转移的调制已被证明。然而，迄今为止，尚未见关于有机光电器件中激发态能量转移的电场调制的研究报道。在此，我们研究了电场对掺杂铱( III )[双(4,6-二氟苯基)吡啶基-N,C ^2′ ]的聚( N-乙烯基咔唑)(PVK)薄膜中能量转移的影响-四(1-吡唑基)硼酸酯 (Fir6) 和 5,6,11,12-四苯基并四苯 (红荧烯) (PVK:Fir6:红荧烯) 以及相应的发光二极管。结合描述电场增强激子解离的 Onsager 模型，我们发现电场提高了薄膜和二极管中从 Fir6 到红荧烯的 Dexter 能量转移速率。 PVK:Fir6:红荧烯发光二极管中的电压依赖性色移可以通过电场增强的 Dexter 能量从 Fir6 到红荧烯的转移来解释。我们的研究结果对于通过电场控制有机光电器件中的能量转移过程以实现理想的应用非常重要。