The challenge of boosting the efficiency of QDSSCs lies in the rational development and design of economical, stable and efficient counter electrode (CE) catalysts for fast and efficient electron transport at the CE/electrolyte interface. Here, we creatively construct Co₉S₈/Cu₇S₄ heterostructure composite CEs using CuCo-Prussian blue analogs (PBA) as precursor by one-step in-situ solvothermal vulcanization method. Work function analysis and systematic electrochemical characterizations reveal that the presence of heterojunctions in the Co₉S₈/Cu₇S₄ can increase the interfacial electric field driving force inside the material, thereby reducing the R_ct at CE/electrolyte interface, promoting the efficient transfer of electrons. Correspondingly, the Co₉S₈/Cu₇S₄ composite CE can improve the stability and compensate for the deficiency of the single component CE through a decent synergistic catalytic effect. Remarkably, the Mn-CdS/CdSe/ZnS co-sensitized QDSSC equipped with Co₉S₈/Cu₇S₄ heterostructure composite CE delivers an optimal conversion efficiency of 8.43% with J_sc = 23.42 mA/cm², V_oc = 0.672 V; FF = 0.54, which was significantly superior to physically mixed CE (PM-Co₉S₈/Cu₇S₄, 6.55%), single-component CE (Cu₇S₄, 5.60%; Co₉S₈, 5.13%) and conventional Brass/Cu₂S CE (4.96%). In briefly, the advanced heterostructure engineering and the abundant, tunable chemical elemental composition of PBA provide new views for the purposeful design of economical and outstanding heterostructured composite CEs.

提高 QDSSC 效率的挑战在于合理开发和设计经济、稳定和高效的对电极 (CE) 催化剂，以在 CE/电解质界面实现快速高效的电子传输。在此，我们创造性地以CuCo-普鲁士蓝类似物（PBA）为前驱体，通过一步原位溶剂热硫化法构建了Co ₉ S ₈ /Cu ₇ S _{4异质结构复合材料CEs。}功函数分析和系统电化学表征表明，Co ₉ S ₈ /Cu ₇ S _{4中存在异质结。}可以增加材料内部的界面电场驱动力，从而降低CE/电解质界面处的R _ct，促进电子的有效转移。相应地，Co ₉ S ₈ /Cu ₇ S ₄复合CE可以通过良好的协同催化作用提高稳定性，弥补单组分CE的不足。值得注意的是，配备 Co ₉ S ₈ /Cu ₇ S _{4异质结构复合材料 CE 的 Mn-CdS/CdSe/ZnS 共敏化 QDSSC 在 J sc} = 23.42 mA/cm ² , V _oc时提供了 8.43% 的最佳转换效率= 0.672 伏；FF = 0.54，明显优于物理混合CE（PM-Co ₉ S ₈ /Cu ₇ S ₄，6.55%）、单组分CE（Cu ₇ S ₄，5.60%；Co ₉ S ₈，5.13%）和传统的黄铜/Cu ₂ S CE (4.96%)。简而言之，PBA先进的异质结构工程和丰富的、可调节的化学元素组成为有目的地设计经济、卓越的异质结构复合材料CE提供了新的视角。