Ternary Ni0.5Zn0.5Fe2O4/carbon nanocomposite as counter electrode for natural dye-sensitized solar cells: Electro-photovoltaic characterizations.

[Display omitted] • Ni 0.5 Zn 0.5 Fe 2 O 4 /carbon (NZF/C) composite was synthesized as counter electrode for DSSCs. • NZF/Cs were characterized using spectro-electrical, optical and cyclic voltammetry tools. • NZF/C-1 containing 50% carbon exhibited comparable efficiency with Pt electrode. • NZF/C-1 CE had a photon conversion efficiency of 7.18% and a FF of 55.57% for Z-907 dye. • NZF/C-1 had a slightly higher charge transfer resistance of 4.33 Ω than Pt-based CE (4.04 Ω) The most notable counter electrode (CE) in dye-sensitized solar cells is platinum (Pt), which is expensive and scarce. Here, Ni 0.5 Zn 0.5 Fe 2 O 4 /carbon (NZF/C) composites containing different ratios of carbon were synthesized and used as novel counter electrodes. NZF/Cs have specific surface areas of 109.3–128.6 m2 g−1, pore sizes of 99.4–119.6 Å, and bandgap energies of 2.36–2.99 eV, according to the characterization results. The catalytic activities of NZF/C CEs were verified by electrochemical impedance spectroscopy and cyclic voltammetry. NZF/Cs demonstrated outstanding catalytic activities in the reduction of I 3 − and had performance comparable to Pt CEs in the dye-sensitized AgNP/TiO 2 DSSCs. For the natural betalain dye, NZF/C-1 CE demonstrated a 2.75% efficiency with a short circuit current density of 4.13 mA cm−2 and a fill factor of 50.71%, which was very competitive with Pt CE's 2.83% efficiency. During 30 days of stability testing, NZF/C-1 CE maintained a photon conversion efficiency of 7.18% and a fill factor of 55.57% for Z-907 synthetic dye. The high electrocatalytic activity of NZF coupled with the good conductivity of carbon black account for NZF/C performance. The results herein show that NZF/C can be used as a cost-effective and efficient substitute for Pt in DSSCs. [ABSTRACT FROM AUTHOR]