(Ag,Cu)(In,Ga)Se₂ solar cells with bandgaps of ≈1.45 eV with a large spread in absorber stoichiometry are characterized with the intention of assessing the effect of composition on the stability of the devices. This material is observed to have a poor diffusion length, leading to very strong dependence upon the depletion region width for charge carrier collection. The depletion width is observed to depend strongly upon the stoichiometry value and shrinks significantly after an initial period of dark storage. It is also seen that the depletion width can be varied strongly through light-soaking and dry-heat treatments, with prolonged annealing leading to detrimental contraction and light soaking leading to expansion which increases current collection. The extent of depletion width variation in response to the treatments is also clearly linked to absorber stoichiometry. Consequently, the device performance, particularly the current output, exhibits a stoichiometry dependence and is considerably affected after each round of treatment. Possible causes of this behavior are discussed.

中文翻译：

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吸收剂化学计量对宽禁带 (Ag,Cu)(In,Ga)Se2 太阳能电池稳定性的影响

(Ag,Cu)(In,Ga)Se ₂具有 ≈1.45 eV 带隙且吸收器化学计量分布较大的太阳能电池的特征在于评估成分对器件稳定性的影响。观察到该材料具有较差的扩散长度，导致对电荷载流子收集的耗尽区宽度有很强的依赖性。观察到耗尽宽度在很大程度上取决于化学计量值，并在黑暗储存的初始阶段后显着缩小。还可以看出，通过光浸泡和干热处理可以显着改变耗尽宽度，长时间退火会导致有害收缩，而光浸泡会导致膨胀，从而增加电流收集。响应于处理的耗尽宽度变化的程度也与吸收剂化学计量明确相关。因此，器件性能，特别是电流输出，表现出化学计量依赖性，并且在每轮处理后受到相当大的影响。讨论了此行为的可能原因。