论文标题
CZTS（1-1-2-）表面I组元素的动力学过程和表面活性剂设计
Kinetic Processes and surfactant design of Group I elements on CZTS (1-1-2-) surface
论文作者
论文摘要
Cu2ZNSNS4（CZTS）是一种有希望的薄膜太阳能电池材料，由地球丰富和无毒的元素组成。然而，存在一个基本的瓶颈，由于既复杂的固有缺陷和有害的次级阶段，都阻碍了设备的性能。最近，在实验上证明，czts共同蒸发生长的Na和k可以扩大晶粒尺寸并抑制Zns二相靠近表面的形成，但原因尚不清楚。我们使用第一个原理计算来研究涉及I组元件（包括Na，K和CS）的CZT（1-1-2-）表面的动力学过程，以证明其表面活性剂效应。探索了涉及I组元素的重建表面的结构和在这些重建表面中Zn Ad-Atom的各种扩散路径。系统比较和讨论了Na，K，CS的表面活性剂作用的优点和关注。尽管I组元素保护地下层上的CU位点，但发现了一个约为400MEV的扩散屏障的无序亚稳态构型。因此，对生长条件的精确控制对于避免亚稳态至关重要。此外，我们的研究为生长过程中表面活性剂效应提供了系统的设计原理。
Cu2ZnSnS4 (CZTS) is a promising thin-film solar-cell material consisted of earth abundant and nontoxic elements. Yet, there exists a fundamental bottle neck that hinders the performance of the device due to complexed intrinsic defects properties and detrimental secondary phases. Recently, it was proven experimentally that Na and K in co-evaporation growth of CZTS can enlarge the grain size and suppress formation of ZnS secondary phase near surface, but the reasons are not well understood. We used first principle calculations to investigate the kinetic processes on CZTS (1-1-2-) surface involving Group I elements, including Na, K, and Cs, to demonstrate their surfactant effects. Both the structure of the reconstructed surfaces involving Group I elements and various diffusion paths of a Zn ad-atom in these reconstructed surfaces were explored. The advantages and concerns of the surfactant effects of Na, K, Cs, were systematically compared and discussed. Although Group I elements protect Cu sites on the subsurface layer, a disordered metastable configuration with a diffusion barrier of about 400meV was found. Therefore, a precise control of growth condition is essential to avoid the metastable phase. In addition, our studies provide a systematical design principle for surfactant effects during the growth.
