Jyothirmai M V, Thapa Ranjit
Department of Physics, SRM University-AP, Amaravati 522502, Andhra Pradesh, India.
SRM Research Institute, SRM Institute of Science and Technology, Kattankulathur 603203, Tamil Nadu, India.
ACS Omega. 2022 Aug 24;7(35):31098-31105. doi: 10.1021/acsomega.2c03223. eCollection 2022 Sep 6.
As a promising candidate for low-cost and eco-friendly thin-film photovoltaics, the emerging quaternary chalcogenide based solar cells have experienced rapid advances over the past decade. Here, we propose quaternary semiconducting chalcogenides CuZnAlSe (CZASe) through cross-substitutions (cation mutations). The nonexistence of imaginary modes in the entire Brillouin zone of CZASe represents the inherent dynamic stability of the system. The electronic, optical, and defect properties of stannite CZASe quaternary semiconducting material was systematically investigated using density functional theory calculations. We have found that the chemical-potential control is very important for growing good-quality crystals and also to avoid secondary-phase formations such as ZnSe, AlZnSe, and CuSe. The observed p-type conductivity is mainly due to antisite defect Cu, which has the lowest formation energy with a relatively deeper acceptor level than that of the Cu vacant site (V). The electronic band structures of vacancies and antisite defects by means of hybrid functional calculations show energy band shifting and energy band narrowing or broadening, which eventually tunes the optical band gap and improves the solar energy-conversion performance of semiconducting CZASe. Our results suggest that the stannite CZASe quaternary chalcogenides could be promising candidates for the efficient earth-abundant thin-film solar cells.
作为低成本且环保的薄膜光伏领域一个有潜力的候选材料，新兴的基于四元硫族化物的太阳能电池在过去十年中取得了快速进展。在此，我们通过交叉取代（阳离子突变）提出了四元半导体硫族化物CuZnAlSe（CZASe）。CZASe整个布里渊区不存在虚模，这代表了该系统固有的动态稳定性。利用密度泛函理论计算系统地研究了类锡矿型CZASe四元半导体材料的电子、光学和缺陷性质。我们发现化学势控制对于生长高质量晶体以及避免诸如ZnSe、AlZnSe和CuSe等二次相的形成非常重要。观察到的p型导电性主要归因于反位缺陷Cu，其具有最低的形成能，且受主能级比Cu空位（V）相对更深。通过杂化泛函计算得到的空位和反位缺陷的电子能带结构显示出能带移动以及能带变窄或变宽，这最终调节了光学带隙并提高了半导体CZASe的太阳能转换性能。我们的结果表明，类锡矿型CZASe四元硫族化物有望成为高效且资源丰富的薄膜太阳能电池的候选材料。
