The manipulation of charge transfer at CuPc/graphene interface has been demonstrated by treating pristine graphene with O₂ plasma. As revealed by in situ ultraviolet photoelectron spectroscopy measurements, a much stronger interfacial charge transfer occurs when the pristine graphene is exposed to O₂ plasma prior to the growth of CuPc films, which is attributed to the increased work function of graphene after O₂ plasma treatment. Moreover, the highest occupied molecular orbital leading edge of CuPc locates at ∼0.80 eV below substrate Fermi level on O₂ plasma treated graphene, whereas it locates at ∼1.10 eV on pristine graphene. Our findings provide detailed information regarding the electronic structure at CuPc/graphene and CuPc/O₂ plasma treated graphene interfaces. The increased work function in combination with the relatively smaller energy offset between the highest occupied molecular orbital of CuPc and Fermi level of O₂ plasma treated graphene facilitates the extraction of holes at the interface, and hence paves the way for improving the performance of graphene-based organic photovoltaic cells.

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The parameters for metal-organic chemical vapor deposition (MOCVD) processes significantly influence the properties of ZnO films, especially the flow stability of the chamber, which is caused by process parameters such as the shape of reaction chamber, the working pressure, the growth temperature, the susceptor rotational speed, the gas flow rate, and the nature of the carrier gas at inlet temperature. These parameters are the preconditions for the formation of high-quality film. Therefore, this study uses Ar as a carrier gas, diethylzinc (DEZn) as a Zn source, and H2O as an oxygen source and adopts the reaction mechanism calculated by quantum chemistry, which includes ten gas reactions and eight surface reactions. The process parameters of a specific reaction chamber model were analyzed based on the computational fluid dynamics method. This study also presents an accurate prediction of the flow regime in the reactor chamber under any operating conditions, without additional experiments, based on an analysis of a great quantity of simulation data. Such research is also significant for selecting the growth parameters relevant to production, providing a specific process growth window, narrowing the debugging scope, and providing a theoretical basis for the development of MOCVD equipment and process debugging.

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