Facile synthesis of an interfacial layer in organic solar cells (OSCs) is important for broadening material designs and upscaling photovoltaic conversion efficiency (PCE). Herein, a mild solution process of spin-coating In(acac)₃ and Ga(acac)₃ isopropanol precursors followed by low-temperature thermal treatment was developed to fabricate In₂O₃ and Ga₂O₃ cathode buffer layers (CBLs). The introduction of In₂O₃ or Ga₂O₃ CBLs endows PM6:Y6-based OSCs with outstanding performance and high PCEs of 16.17% and 16.01%, respectively. Comparison studies present that the In₂O₃ layer possesses a work function (WF) of 4.58 eV, which is more favorable for the formation of ohmic contact compared with the Ga₂O₃ layer with a WF of 5.06 eV and leads to a higher open circuit voltage for the former devices. Electrochemical impedance spectroscopy was performed to reveal how In₂O₃ and Ga₂O₃ affect the internal charge transfer and the origin of their performance difference. Although In₂O₃ possesses lower series resistance loss, Ga₂O₃ has a higher recombination resistance, which enhances the device fill factor and compensates for its series resistance loss to some extent. Comparative analysis of the photo-physics of In₂O₃ and Ga₂O₃ suggests that both are excellent CBLs for highly efficient OSCs.

易于合成有机太阳能电池（OSC）中的界面层对于拓宽材料设计和提高光伏转换效率（PCE）至关重要。在此，开发了旋涂In（acac）₃和Ga（acac）₃异丙醇前体并随后进行低温热处理的温和溶液工艺，以制造In ₂ O ₃和Ga ₂ O ₃阴极缓冲层（CBL）。In ₂ O ₃或Ga ₂ O ₃ CBL的引入使基于PM6：Y6的OSC具有出色的性能和高PCE，分别达到16.17％和16.01％。比较研究表明，In ₂O ₃层的功函数（WF）为4.58 eV，与WF为5.06 eV的Ga ₂ O ₃层相比，它更有利于形成欧姆接触，并导致前者的开路电压更高。进行了电化学阻抗谱分析，以揭示In ₂ O ₃和Ga ₂ O _3如何影响内部电荷转移及其性能差异的根源。尽管In ₂ O ₃具有较低的串联电阻损耗，但Ga ₂ O ₃具有更高的复合电阻，从而提高了器件的填充系数，并在一定程度上补偿了其串联电阻损耗。对In ₂ O ₃和Ga ₂ O _3的光物理性质的比较分析表明，对于高效OSC，两者都是出色的CBL。