Han Fanjunjie, Yu Tong, Qu Xin, Bergara Aitor, Yang Guochun
Centre for Advanced Optoelectronic Functional Materials Research and Key Laboratory for UV Light-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, People's Republic of China.
State Key Laboratory of Metastable Materials Science & Technology and Key Laboratory for Microstructural Material Physics of Hebei Province, School of Science, Yanshan University, Qinhuangdao 066004, People's Republic of China.
J Phys Condens Matter. 2021 Apr 21;33(17). doi: 10.1088/1361-648X/abe269.
Exploring new two-dimensional (2D) materials is of great significance for both basic research and practical applications. Although boron can form various 3D and 2D allotropes due to its ease of forming multi-center bonds, the coexistence of honeycomb and kagome boron structures has never been observed in any 2D material yet. In this article we apply first-principle swarm structural searches to predict the existence of a stable MnBstructure, consisting of a sandwich of honeycomb and kagome borophenes. More interestingly, a MnBnanosheet is a semiconductor with a band gap of 1.07 eV and a high optical absorption in a broad band, which satisfies the requirements of a very good photovoltaic material. Upon moderate strain, MnBundergoes a conversion from an indirect to a direct band gap semiconductor. The power conversion efficiency of a heterostructure solar cell made of MnBis up to 18%. The MnBnanosheet shows a robust dynamical and thermal stability, stemming from the presence of intra- and interlayer multi-center σ and π bonds. These characteristics make MnBa promising photovoltaic material.
探索新型二维（2D）材料对于基础研究和实际应用都具有重要意义。尽管硼由于易于形成多中心键而能形成各种三维和二维同素异形体，但在任何二维材料中从未观察到蜂窝状和 Kagome 硼结构的共存。在本文中，我们应用第一性原理群结构搜索来预测一种稳定的 MnB 结构的存在，该结构由蜂窝状和 Kagome 硼烯的三明治结构组成。更有趣的是，MnB 纳米片是一种半导体，带隙为 1.07 eV，在宽带中具有高光学吸收，满足了非常好的光伏材料的要求。在适度应变下，MnB 会从间接带隙半导体转变为直接带隙半导体。由 MnB 制成的异质结构太阳能电池的功率转换效率高达 18%。MnB 纳米片表现出强大的动力学和热稳定性，这源于层内和层间多中心 σ 和 π 键的存在。这些特性使 MnB 成为一种有前途的光伏材料。
