The development of counter electrode (CE) catalytic materials with cost-effective and excellent catalytic activity, transparency, good stability, and simple fabrication process is urgently needed for bifacial quasi-solid-state dye-sensitized solar cells (BQDSSCs). Herein, NiS(1.97)nanoparticles, In(2.77)S(4)and NiIn(2)S(4)nanosheet structures were successfully constructed by a one-step in situ solvothermal method on an FTO glass substrate to act as counter electrodes (CEs). The electrochemical results revealed that the NiIn(2)S(4)interconnected nanosheet CE exhibited enhanced electrocatalytic activity for the reduction of I-3(-), which can be attributed to the unique structure with a large contact area for the electrolyte and FTO substrate, enhancing electron transfer and providing effective catalytic sites. The BQDSSCs based on the NiIn2S4CE showed the superior front and rear illuminationJ(sc)values of 15.27 and 9.13 mA cm(-2), and power conversion efficiencies (PCEs) of 8.00% and 4.59%, respectively, which were higher than those of binary NiS(1.97)and In2.77S4, and comparable to the Pt CE with front and rear efficiencies of 7.42% and 3.93%, respectively. Furthermore, the NiIn2S4CE film displayed a high multiple on-off switching response and good stability, suggesting that ternary sulfides could be promising alternatives for CE materials in BQDSSCs. [GRAPHICS] .