¹ Shandong Key Laboratory of Green Electricity&Hydrogen Science and Technology, School of Chemical Engineering, Shandong Institute of Petroleum and Chemical Technology, Dongying, 257061, PR China

* Correspondence: Zhangq253@nenu.edu.cn (Qiu Zhang)

Quantum dot-sensitized solar cells (QDSSCs) have emerged as a prominent research focus, driven by their low cost, simple fabrication process, and a theoretical power conversion efficiency (PCE) that can reach as high as 44%. However, the PCE of QDSSCs remains constrained by the electrocatalytic performance and long-term stability of the counter electrodes (CEs). The single MoS₂-CE has problems such as insufficient electrocatalytic activity and short lifetime. Herein, a PMo₁₂/MoS₂ composite was synthesized via simple hydrothermal method and fabricated into CEs by screen-printing for CdS-sensitized QDSSCs. The electrocatalytic and photovoltaic performance of CEs were systematically evaluated using EIS, Tafel, LSV, OCVD, and J-V characterization. The results confirmed that moderate PMo₁₂ doping effectively enhances the electrocatalytic activity, conductivity, and stability of MoS₂-CE. CdS-sensitized QDSSCs based on PMo₁₂/MoS₂-1 composite CEs can achieve a PCE of 3.21%, nearly 58% higher than that of QDSSCs (2.01%) equipped with single MoS₂-CEs. This study provides a feasible technical path for preparing high-performance composite CEs doped with polyoxometalate.