In this paper, two new monolayers, namely PtOS and PtOSe, are theoretically predicted using first-principles calculations. Structural, electronic, optical and thermoelectric properties are explored using full-potential linearized augmented plane-wave (FP-LAPW) method and the semiclassical Boltzmann transport theory. Predicted two-dimensional (2D) materials show good dynamical, thermodynamic and structural stability. Calculated electronic structures indicate the indirect gap semiconductor nature of the PtOS and PtOSe single layers with energy gap of 1.346(2.436) and 0.978(1.978) eV as calculated with the WC(HSE06) functional, respectively. Density of states spectra and valence charge distribution maps suggest a mix of covalent and ionic characters of the chemical bonds. 2D materials at hand exhibit good absorption property in the visible regime with coefficient value reaching the order of 10⁵/cm, even much larger in the ultraviolet, suggesting the promising optoelectronic applicability. Finally, the thermoelectric parameters including electrical conductivity, thermal conductivity, Seebeck coefficient, power factor and figure of merit are determined and analyzed. Results indicate prospective thermoelectric performance of both considered single layers as demonstrated by large figure of merit close to unity. Our work introduces two new 2D multifunctional materials that may possess potential applications in the optoelectronic and thermoelectric nano-devices.

在本文中，使用第一原理计算理论上预测了两个新的单层，即PtOS和PtOSe。使用全势线性化增强平面波（FP-LAPW）方法和半经典玻尔兹曼输运理论探索结构，电子，光学和热电性质。预测的二维（2D）材料显示出良好的动力学，热力学和结构稳定性。计算得出的电子结构表明PtOS和PtOSe单层的间接间隙半导体性质，其能隙分别为WC（HSE06）eV为1.346（2.436）和0.978（1.978）eV。状态光谱和价态电荷分布图的密度暗示了化学键的共价和离子特征的混合。⁵ / cm，甚至在紫外线下更大，表明有希望的光电适用性。最后，确定并分析了热电参数，包括电导率，热导率，塞贝克系数，功率因数和品质因数。结果表明这两个被考虑的单层的预期热电性能，如接近单位的大品质因数所示。我们的工作介绍了两种新型的2D多功能材料，它们可能在光电和热电纳米器件中具有潜在的应用。