Abstract Two strategies for enhancing photovoltaic (PV) performance in chalcopyrite solar cells were investigated: Cu1−xKxIn1−yGaySe2 absorbers with low K content (K/(K+Cu), or x ~ 0.07) distributed throughout the bulk, and CuIn1−yGaySe2 absorbers with KIn1−yGaySe2 grown on their surfaces. Distributing K throughout the bulk absorbers improved power conversion efficiency, open-circuit voltage (VOC) and fill factor (FF) for Ga/(Ga+In) of 0, 0.3 and 0.5. Surface KIn1−yGaySe2 and bulk x ~ 0.07 Cu1−xKxIn1−yGaySe2 films with Ga/(Ga+In), or y of 0.3 and 0.5 also had improved efficiency, VOC, and FF, relative to CuIn1−yGaySe2 baselines. On the other hand, y ~ 1 absorbers did not benefit from K introduction. Similar to Cu1−xKxInSe2, the formation of Cu1−xKxGaSe2 alloys was favored at low temperatures and high Na supply by the substrate, relative to the formation of mixed-phase CuGaSe2 + KGaSe2. KIn1−yGaySe2 alloys were grown for the first time, as evidenced by X-ray diffraction and ultraviolet/visible spectroscopy. For all Ga/(Ga+In) compositions, the surface KIn1−yGaySe2 absorbers had superior PV performance in buffered and buffer-free devices. However, the bulk x ~ 0.07 absorbers only outperformed the baselines in buffered devices. The data demonstrate that KIn1−yGaySe2 passivates the surface of CuIn1−yGaySe2 to increase efficiency, VOC, and FF, while bulk Cu1−xKxIn1−yGaySe2 absorbers with x ~ 0.07 enhance efficiency, VOC, and FF by some other mechanism.

中文翻译：

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Cu 1−x K x In 1−y Ga y Se 2 太阳能电池中K的表面和体效应

摘要 研究了提高黄铜矿太阳能电池光伏 (PV) 性能的两种策略：分布在整个块体中的低 K 含量 (K/(K+Cu) 或 x ~ 0.07) 的 Cu1−xKxIn1−yGaySe2 吸收剂和 CuIn1−yGaySe2在其表面生长有 KIn1−yGaySe2 的吸收剂。在整个体吸收器中分布 K 提高了功率转换效率、开路电压 (VOC) 和 Ga/(Ga+In) 的填充因子 (FF) 为 0、0.3 和 0.5。相对于 CuIn1-yGaySe2 基线，具有 Ga/(Ga+In) 或 y 为 0.3 和 0.5 的表面 KIn1-yGaySe2 和块体 x ~ 0.07 Cu1-xKxIn1-yGaySe2 薄膜也具有更高的效率、VOC 和 FF。另一方面，y ~ 1 吸收器没有受益于 K 的引入。与 Cu1-xKxInSe2 类似，Cu1-xKxGaSe2 合金的形成在低温和基板提供的高 Na 条件下是有利的，相对于混合相 CuGaSe2 + KGaSe2 的形成。X 射线衍射和紫外/可见光谱证明了 KIn1-yGaySe2 合金的首次生长。对于所有 Ga/(Ga+In) 组合物，表面 KIn1-yGaySe2 吸收剂在缓冲和无缓冲器件中具有优异的 PV 性能。然而，体积 x ~ 0.07 吸收器仅优于缓冲设备中的基线。数据表明，KIn1-yGaySe2 钝化了 CuIn1-yGaySe2 的表面以提高效率、VOC 和 FF，而 x ~ 0.07 的块状 Cu1-xKxIn1-yGaySe2 吸收剂通过一些其他机制提高效率、VOC 和 FF。表面 KIn1−yGaySe2 吸收器在缓冲和无缓冲器件中具有优异的 PV 性能。然而，体积 x ~ 0.07 吸收器仅优于缓冲设备中的基线。数据表明，KIn1-yGaySe2 钝化了 CuIn1-yGaySe2 的表面以提高效率、VOC 和 FF，而 x ~ 0.07 的块状 Cu1-xKxIn1-yGaySe2 吸收剂通过一些其他机制提高效率、VOC 和 FF。表面 KIn1−yGaySe2 吸收器在缓冲和无缓冲器件中具有优异的 PV 性能。然而，体积 x ~ 0.07 吸收器仅优于缓冲设备中的基线。数据表明，KIn1-yGaySe2 钝化了 CuIn1-yGaySe2 的表面以提高效率、VOC 和 FF，而 x ~ 0.07 的块状 Cu1-xKxIn1-yGaySe2 吸收剂通过一些其他机制提高效率、VOC 和 FF。