The electronic and optical properties of the adsorption of alkali metals (Li, Na, K, Rb, Cs) on graphitic carbon nitride (g-C3N[Formula: see text] were calculated and studied based on the first principles of density functional theory. The results investigate that alkali metals adsorbed g-C3N4 has metallic properties, while intrinsic g-C3N4 was semiconducting. Importantly, the charge density differential investigated the charge transfer discovered between the alkali metal and the g-C3N4 monolayer. Meanwhile, the charges (electrons) transfer from the alkali metals to the g-C3N4 system leading to the increase of most carriers in the g-C3N4 system, reducing the resistance of sensors, which is conducive to sensor detection applications. The work function of g-C3N4 decreased from 4.82 eV to 4.09 eV. Especially, the work function of Cs-adsorbed g-C3N4 is the lowest at 4.09 eV, and the reduction rate is 15.15 %, indicating it easier to emit electrons from an external electric field. Moreover, the absorption spectrum of the alkali metal adsorbed on g-C3N4 in the visible light range shows absorption peaks at 380 nm, 412 nm, 420 nm and 476 nm, which cover the visible light area. Thus, the alkali metals adsorbed g-C3N4 system can be used for visible light catalytic. Adsorption of alkali metals can expand the application of g-C3N4 in optoelectronic devices.

中文翻译：

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碱金属在石墨氮化碳上的吸附：第一性原理研究

碱金属（Li、Na、K、Rb、Cs）吸附在石墨氮化碳（gC）上的电子和光学性质3N[公式：见正文]是根据密度泛函理论的第一原理计算和研究的。结果调查了碱金属吸附 gC3ñ4具有金属特性，而固有的 gC3ñ4是半导体。重要的是，电荷密度差研究了碱金属和 gC 之间发现的电荷转移3ñ4单层。同时，电荷（电子）从碱金属转移到 gC3ñ4系统导致gC中大多数运营商的增加3ñ4系统，降低传感器的电阻，有利于传感器检测应用。gC的功函数3ñ4从 4.82 eV 降至 4.09 eV。特别是，Cs 吸附 gC 的功函数3ñ4最低为 4.09 eV，还原率为 15.15 %，表明更容易从外部电场中发射电子。此外，gC 上吸附的碱金属的吸收光谱3ñ4在可见光范围内，在 380 nm、412 nm、420 ​​nm 和 476 nm 处有吸收峰，覆盖了可见光区域。因此，碱金属吸附 gC3ñ4可用于可见光催化体系。吸附碱金属可扩大gC的应用3ñ4在光电器件中。