Nanoporous NiO nanosheets-based nanohybrid catalyst for efficient reduction of triiodide ions

Abstract This study focuses on the synthesis of nanoporous NiO nanosheets hybridized with PEDOT:PSS, Cdot and Pt nanoparticles and screening the catalytic activities for the regeneration of iodide ions from triiodide ions in liquid-junction photovoltaic devices. Due to a special hexagonal structure of NiO nanosheets, Pt nanoparticles and Cdot are easily immobilized on the surface and walled holes of NiO nanosheets with the size in the range of 2–5 nm. The electrochemical performances indicate the catalytic activity of counter electrodes (CEs) follows the sequence of NiO-Pt > Pt sputtering > NiO-Cdot > NiO-PEDOT:PSS > NiO. Thus, the photovoltaic performances provide the efficiency of 1.73, 5.51, 8.25 and 9.66% for cells with NiO, NiO-PEDOT:PSS, NiO-Cdot and NiO-Pt CEs, respectively, which are compared to the device using the Pt electrode (8.86%). The findings in this work are promising for developing highly efficient Pt-free catalyst materials for CEs of devices.