Abstract Carbon nitride two-dimensional (2D) materials are among the most attractive class of nanomaterials, with wide range of application prospects. As a continuous progress, most recently, two novel carbon nitride 2D lattices of C3N5 and C3N4 have been successfully experimentally realized. Motivated by these latest accomplishments and also by taking into account the well-known C3N4 triazine-based graphitic carbon nitride structures, we predicted two novel C3N6 and C3N4 counterparts. We then conducted extensive density functional theory simulations to explore the thermal stability, mechanical, electronic and optical properties of these novel nanoporous carbon-nitride nanosheets. According to our results all studied nanosheets are found to exhibit desirable thermal stability and mechanical properties. Non-equilibrium molecular dynamics simulations on the basis of machine learning interatomic potentials predict ultralow thermal conductivities for these novel nanosheets. Electronic structure analyses confirm direct band gap semiconducting electronic character and optical calculations reveal the ability of these novel 2D systems to adsorb visible range of light. Extensive first-principles based results by this study provide a comprehensive vision on the stability, mechanical, electronic and optical responses of C3N4, C3N5 and C3N6 as novel 2D semiconductors and suggest them as promising candidates for the design of advanced nanoelectronics and energy storage/conversion systems.

中文翻译：

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纳米多孔 C3N4、C3N5 和 C3N6 纳米片；具有低热导率和吸引人的光学/电子特性的新型强半导体

摘要 氮化碳二维（2D）材料是最具吸引力的一类纳米材料，具有广泛的应用前景。作为一个持续的进展，最近，C3N5 和 C3N4 两种新型氮化碳二维晶格已成功通过实验实现。受这些最新成就的启发，并考虑到众所周知的 C3N4 三嗪基石墨碳氮化物结构，我们预测了两种新颖的 C3N6 和 C3N4 对应物。然后，我们进行了广泛的密度泛函理论模拟，以探索这些新型纳米多孔碳氮化物纳米片的热稳定性、机械、电子和光学特性。根据我们的结果，发现所有研究的纳米片都表现出理想的热稳定性和机械性能。基于机器学习原子间势的非平衡分子动力学模拟预测了这些新型纳米片的超低热导率。电子结构分析证实了直接带隙半导体电子特性，光学计算揭示了这些新型 2D 系统吸收可见光范围的能力。本研究基于第一性原理的广泛结果为 C3N4、C3N5 和 C3N6 作为新型二维半导体的稳定性、机械、电子和光学响应提供了全面的视角，并建议它们作为先进纳米电子学和能量存储/转换设计的有前途的候选者系统。电子结构分析证实了直接带隙半导体电子特性，光学计算揭示了这些新型 2D 系统吸收可见光范围的能力。本研究基于第一性原理的广泛结果为 C3N4、C3N5 和 C3N6 作为新型二维半导体的稳定性、机械、电子和光学响应提供了全面的视角，并建议它们作为先进纳米电子学和能量存储/转换设计的有希望的候选者系统。电子结构分析证实了直接带隙半导体电子特性，光学计算揭示了这些新型 2D 系统吸收可见光范围的能力。本研究基于第一性原理的广泛结果为 C3N4、C3N5 和 C3N6 作为新型二维半导体的稳定性、机械、电子和光学响应提供了全面的视角，并建议它们作为先进纳米电子学和能量存储/转换设计的有希望的候选者系统。