High‐Performance Cobalt Selenide and Nickel Selenide Nanocomposite Counter Electrode for Both Iodide/Triiodide and Cobalt(II/III) Redox Couples in Dye‐Sensitized Solar Cells

Abstract

The nanocomposites of cobalt selenide and nickel selenide (Co 0.85 Se/Ni 0.85 Se) were successfully fabricated on FTO glass by a facile co-electrodeposition method at ambient temperature. Nanocomposite films were used as electrocatalysts in dye-sensitized solar cell counter electrodes for regeneration of both iodide/triiodide and cobalt(II/III) redox couples. Co 0.85 Se/Ni 0.85 Se were mainly composed of nanoflakes and nanoparticles. It is noted that such nanostructure generated by nanoparticles embedded with 2D nanoflakes led to high active sites and was accessible to cobalt(II/III) electrolyte, delivering better catalytic activity for the reduction of larger volume cobalt(II/III). As a result, for cobalt(II/III) electrolyte, the Co 0.85 Se/Ni 0.85 Se based dye-sensitized solar cell performed significantly improved efficiency than that of Pt and Co 0.85 Se. Meanwhile, the Co 0.85 Se/Ni 0.85 Se based dye-sensitized solar cell held comparable energy conversion efficiency to that of Pt and Co 0.85 Se for iodide/triiodide electrolyte.

Petal-like cobalt selenide nanosheets used as counter electrode in high efficient dye-sensitized solar cells

“…3, it can be seen that the PCE of Co 0.85 Se-160 is 8.00 %, which is higher than that of other Co 0.85 Se nanosheet CEs. The DSSC with Co 0.85 Se-160 shows excellent photovoltaic behavior, even better than the DSSC with Pt CE in the same conditions which only achieved PCE of 7.83 %, the efficiency of the DSSC based on Co 0.85 Se-160 electrode is comparable with the reports by others [26,27]. The improvement in the photovoltaic performance for the DSSCs based on Co 0.85 Se CEs is mainly due to the small increases in V OC and FF.…”

Metal Chalcogenides (MxEy; E = S, Se, and Te) as Counter Electrodes for Dye–Sensitized Solar Cells: An Overview and Guidelines

“…Moreover, ternary nickel cobalt selenide CEs have also drawn significant attention for their performance as CEs for DSSCs. [126][127][128][134][135][136] Theerthagiri et al [126] synthesized Ni 1Àx Co x Se 2 (0 ≤ x ≤ 1) CEs through a one-step hydrothermal procedure and found that after optimization of the composition, Ni 0.5 Co 0.5 Se 2 CE showed excellent electrocatalytic activity, and the corresponding DSSC achieved good PCE (6.02%) compared to the Pt-based DSSC (6.11%). Following this work, Qian et al [127] prepared Ni x Co 1Àx Se (x ¼ 0.33, 0.5, 0.67) CEs to study the effect of stoichiometric ratios on the catalytic activity and photovoltaic performance.…”

Counter electrode materials combined with redox couples in dye- and quantum dot-sensitized solar cells

“…39 In addition, heteroatom-containing graphene was also synthesized served as CEs in DSCs system for Co redox couples. 42 However, the poor adhesion of transition metal compounds to FTO glasses and the requirement of a large quantity of compounds load for high efficiency still limited the application of these materials. The resulting PCEs were all better than Pt.…”