Understanding charge transfer processes between graphene and functional materials is crucial from the perspectives of fundamental sciences and potential applications, including electronic devices, photonic devices, and sensors. In this study, we present the charge transfer behavior of graphene and amine-rich polyethyleneimine (PEI) upon CO₂ exposure, which was significantly improved after introduction of hygroscopic polyethylene glycol (PEG) in humid air. By blending PEI and PEG, the number of protonated amine groups in PEI was remarkably increased in the presence of water molecules, leading to a strong electron doping effect on graphene. The presence of CO₂ gas resulted in a large change in the resistance of PEI/PEG-co-functionalized graphene because of the dramatic reduction of said doping effect, reaching a maximum sensitivity of 32% at 5,000 ppm CO₂ and an applied bias of 0.1 V in air with 60% relative humidity at room temperature. This charge transfer correlation will facilitate the development of portable graphene-based sensors for real-time gas detection and the extension of the applications of graphene-based electronic and photonic devices.

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从基础科学和潜在应用（包括电子设备，光子设备和传感器）的角度出发，了解石墨烯与功能材料之间的电荷转移过程至关重要。在这项研究中，我们介绍了石墨烯和富含胺的聚乙烯亚胺（PEI）在CO ₂暴露下的电荷转移行为，在潮湿空气中引入吸湿性聚乙二醇（PEG）后，电荷转移行为得到了显着改善。通过将PEI和PEG混合，在水分子存在下，PEI中的质子化胺基数量显着增加，从而导致对石墨烯的强电子掺杂作用。CO ₂的存在气体导致PEI / PEG共官能化石墨烯的电阻变化很大，因为该掺杂效应显着降低，在5,000 ppm CO _2下达到最大灵敏度32％，在空气中施加0.1 V偏压。室温下相对湿度为60％。这种电荷转移相关性将促进用于实时气体检测的便携式基于石墨烯的传感器的开发以及基于石墨烯的电子和光子设备的应用范围的扩展。

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