Abstract We explore graphene as interface modifier for electrodes in optoelectronic organic devices by measuring the electrical properties of ITO/graphene and ITO/Cr/graphene. For this purpose, exfoliated graphene (EG) was electrochemically synthesized and deposited by spray-pyrolysis. The built-in voltage (Vbi) values were 450 mV for the ITO/CuPc/Al reference, 750 mV for ITO/Cr/graphene/CuPc/Al and 1000 mV for ITO/graphene/CuPc/Al device structures. From these results, we estimate the work functions as 3.20 eV, 3.45 eV and 4.75 eV for ITO/EG, ITO/Cr/EG and ITO. To understand how the work function changes, we carried out first-principles calculations based on density-functional theory (DFT) where Cr work function (~4.2 eV) is not modified by the deposition of pristine graphene; however there is a substantial increase (from 4.2 eV to 5.2 eV), upon deposition of graphene oxide (GO), resulting from a complete transfer of O atoms from the GO sheet to the Cr surface forming a thin layer of chromium oxide.

中文翻译：

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石墨烯作为 ITO 和 ITO-Cr 电极中的界面改性剂

摘要 我们通过测量 ITO/石墨烯和 ITO/Cr/石墨烯的电学性质，探索石墨烯作为光电有机器件中电极的界面改性剂。为此，剥离的石墨烯（EG）被电化学合成并通过喷雾热解沉积。ITO/CuPc/Al 参考的内置电压 (Vbi) 值为 450 mV，ITO/Cr/石墨烯/CuPc/Al 为 750 mV，ITO/石墨烯/CuPc/Al 器件结构为 1000 mV。根据这些结果，我们估计 ITO/EG、ITO/Cr/EG 和 ITO 的功函数为 3.20 eV、3.45 eV 和 4.75 eV。为了了解功函数如何变化，我们基于密度泛函理论 (DFT) 进行了第一性原理计算，其中 Cr 功函数 (~4.2 eV) 不会因原始石墨烯的沉积而改变；但是有大幅增加（从 4.2 eV 到 5.2 eV），