Although silver (Ag) substitution offers several benefits in eliminating bulk defects and facilitating interface type inversion for Cu₂ZnSn(S,Se)₄ (CZTSSe) photovoltaic (PV) technology, its further development is still hindered by the fairly low electrical conductivity due to the significant decrease of acceptors amount. In this work, a versatile Li–Ag co-doping strategy is demonstrated to mitigate the poor electrical conductivity arising from Ag through direct incorporating Li via postdeposition treatment (PDT) on top of the Ag-substituted CZTSSe absorber. Depth characterizations demonstrate that Li incorporation increases p-type carrier concentration, improves the carrier collection within the bulk, reduces the defects energy level as well as inverts the electric field polarity at grain boundaries (GBs) for Ag-substituted CZTSSe system. Benefiting from this lithium-assisted complex engineering of electrical performance both in grain interior (GI) and GBs, the power conversion efficiency (PCE) is finally increased from 9.21% to 10.29%. This systematic study represents an effective way to overcome the challenges encountered in Ag substitution, and these findings support a new aspect that the synergistic effects of double cation dopant will further pave the way for the development of high efficiency kesterite PV technology.

尽管银（Ag）替代在消除体缺陷和促进Cu ₂ ZnSn（S，Se）_4的界面类型反转方面提供了许多好处（CZTSSe）光伏（PV）技术，由于受体数量的显着减少，其电导率仍然很低，仍然阻碍了它的进一步发展。在这项工作中，展示了一种通用的Li-Ag共掺杂策略，可通过在Ag取代的CZTSSe吸收体上通过后沉积处理（PDT）直接掺入Li来减轻由Ag引起的不良电导率。深度表征表明，掺入Li会增加p型载流子浓度，改善体中的载流子收集，降低缺陷能级，以及使Ag取代的CZTSSe体系晶界（GBs）处的电场极性反转。受益于这种锂辅助的复杂谷物内部电气（GI）和GB的电气性能工程，功率转换效率（PCE）最终从9.21％提高到10.29％。这项系统的研究代表了克服银替代过程中遇到的挑战的有效途径，这些发现支持了一个新的方面，即双阳离子掺杂剂的协同效应将进一步为高效硅藻土光伏技术的发展铺平道路。