Cu(In,Ga)(S,Se)₂ (CIGS) thin film solar cells require appropriate depth and lateral distributions of alkali metal dopants and gallium to attain world record photovoltaic energy conversion. The two requirements are interdependent because sodium is known to hamper In/Ga interdiffusion in polycrystalline films. However, such a fact is challenged by recent findings where sodium appears to enhance In/Ga interdiffusion in monocrystalline films. This contribution reviews closely the two cases to the benefits of grain boundary engineering in CIGS. A computational model reveals why Na induces In accumulation at CIGS grain boundaries, confining Ga to grain interiors. The positive technological implications for wider gap chalcopyrites are stressed.

中文翻译：

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狐狸和猎犬：Cu（In，Ga）Se2太阳能电池中的深入和晶粒内Na掺杂和Ga分级

Cu（In，Ga）（S，Se）₂（CIGS）薄膜太阳能电池需要碱金属掺杂剂和镓的适当深度和横向分布，才能获得世界纪录的光伏能量转换。这两个条件是相互依赖的，因为已知钠会阻碍In / Ga在多晶膜中的相互扩散。然而，最近的发现挑战了这一事实，钠似乎增强了单晶膜中的In / Ga互扩散。本文对CIGS中晶界工程的两种情况进行了详尽的回顾。一个计算模型揭示了Na为何会在CIGS晶界处诱导In积累，从而将Ga限制在晶粒内部。强调了对较宽的间隙黄铜矿的积极技术意义。