In situ grown NiIn2S4 nanosheets as counter electrode for bifacial quasi-solid-state dye-sensitized solar cells

Abstract

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, NiS1.97 nanoparticles, In2.77S4 and NiIn2S4 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 NiIn2S4 interconnected nanosheet CE exhibited enhanced electrocatalytic activity for the reduction of I3−, 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 NiIn2S4 CE showed the superior front and rear illumination Jsc 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 NiS1.97 and In2.77S4, and comparable to the Pt CE with front and rear efficiencies of 7.42% and 3.93%, respectively. Furthermore, the NiIn2S4 CE 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. The NiIn2S4 nanosheet BQDSSC yields front and rear PCEs of 8.00 and 4.59%, higher than those of NiS1.97, In2.77S4, and Pt CEs, respectively.