Gorai Prashun, Krasikov Dmitry, Grover Sachit, Xiong Gang, Metzger Wyatt K, Stevanović Vladan
Colorado School of Mines, Golden, CO 80401, USA.
First Solar Inc., Santa Clara, CA 95050, USA.
Sci Adv. 2023 Feb 24;9(8):eade3761. doi: 10.1126/sciadv.ade3761.
There is widespread interest in reaching the practical efficiency of cadmium telluride (CdTe) thin-film solar cells, which suffer from open-circuit voltage loss due to high surface recombination velocity and Schottky barrier at the back contact. Here, we focus on back contacts in the superstrate configuration with the goal of finding new materials that can provide improved passivation, electron reflection, and hole transport properties compared to the commonly used material, ZnTe. We performed a computational search among 229 binary and ternary tetrahedrally bonded structures using first-principles methods and transport models to evaluate critical material design criteria, including phase stability, electronic structure, hole transport, band alignments, and p-type dopability. Through this search, we have identified several candidate materials and their alloys (AlAs, AgAlTe, ZnGeP, ZnSiAs, and CuAlTe) that exhibit promising properties for back contacts. We hope that these new material recommendations and associated guidelines will inspire new directions in hole transport layer design for CdTe solar cells.
人们对实现碲化镉（CdTe）薄膜太阳能电池的实际效率有着广泛的兴趣，这种电池由于高表面复合速度和背接触处的肖特基势垒而存在开路电压损失。在此，我们聚焦于覆层结构中的背接触，目标是找到与常用材料碲化锌（ZnTe）相比，能够提供更好的钝化、电子反射和空穴传输性能的新材料。我们使用第一性原理方法和输运模型，在229种二元和三元四面体键合结构中进行了计算搜索，以评估关键的材料设计标准，包括相稳定性、电子结构、空穴传输、能带排列和p型掺杂能力。通过这次搜索，我们确定了几种具有背接触前景特性的候选材料及其合金（砷化铝（AlAs）、银铝碲（AgAlTe）、锌锗磷（ZnGeP）、锌硅砷（ZnSiAs）和铜铝碲（CuAlTe））。我们希望这些新的材料推荐和相关指导方针将为CdTe太阳能电池的空穴传输层设计带来新的方向。
