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Remodelling hierarchical NiCo2O4@ZnS nanorods with multi-walled carbon nanotubes as a counter electrode for dye-sensitized solar cell applications
(2026-12-01)
Nukunudompanich, Methawee
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Nachaithong, Theeranuch
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Phumuen, Phatcharin
;
Wannabut, Wassana
;
Kunbuala, Neeraphat
A hierarchical NiCo<inf>2</inf>O<inf>4</inf>@ZnS/MWCNT (NCO@Z-MWCNTs) nanocomposite was synthesized to serve as a platinum-free counter electrode for dye-sensitized solar cells (DSSCs). The nanocomposite comprised spinel NiCo<inf>2</inf>O<inf>4</inf> nanorods, ZnS associated with the surface of the nanorods, and an interconnected multi-walled carbon nanotube (MWCNT) network, and it was synthesized via a low-temperature solution-based hydrothermal method. XRD confirmed the presence of cubic NiCo<inf>2</inf>O<inf>4</inf> and zinc blende ZnS phases, while FESEM–EDS and XPS analyses verified the incorporation of ZnS and the formation of a conductive carbon framework interconnecting adjacent nanorods. ZnS, rather than acting as an isolated catalytic component, was considered to contribute additional sulfide-related surface sites and to modulate the interfacial electronic environment of the NiCo<inf>2</inf>O<inf>4</inf> nanorods, which likely facilitated redox reactions involving the I−/I<inf>3</inf>− couple. Meanwhile, the MWCNT network established continuous electron transport pathways, effectively reducing interfacial resistance and enhancing charge-transfer efficiency. Thermogravimetric and electrochemical analyses revealed enhanced thermal stability, improved redox kinetics, and a significant reduction in charge-transfer resistance compared with pristine NiCo<inf>2</inf>O<inf>4</inf>.The optimized NCO@Z–MWCNT 9wt% counter electrode achieved a power conversion efficiency of 10.03% under AM 1.5 G illumination, exceeding that of the Pt reference device (9.6%). Overall, the improved performance was attributed to the combined contributions of ZnS surface modification and the conductive MWCNT network, which together enhanced charge transport and electrocatalytic activity. This work demonstrates a scalable strategy for developing cost-effective, durable, and high-performance counter electrodes for dye-sensitized solar cells.
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New hybrid high performance dye-sensitized solar cells using CoNi2Se4@SiO2 core-shell integrated with graphene quantum dots as counter electrodes
(2026-10-01)
Areerob, Yonrapach
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Nachaithong, Theeranuch
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Phumuen, Phatcharin
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Wannabut, Wassana
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Nijpanich, Supinya
A novel CoNi₂Se₄@SiO₂ core–shell nanostructure decorated with graphene quantum dots (CNS@Si–GQDs) was synthesized via a simple hydrothermal method and investigated as a Pt-free counter electrode for dye-sensitized solar cells (DSSCs). The optimized CNS@Si–GQDs electrode with 7 ppm GQD loading exhibited excellent electrocatalytic activity toward the I₃−/I− redox reaction, delivering a photoelectric conversion efficiency (PCE) of 8.10%, slightly higher than that of the conventional Pt electrode (8.03%). The optimized device also achieved a high short-circuit current density (Jsc) of 18.67 mA cm−2, with a Voc of 0.75 V and a fill factor (FF) of 0.57. Electrochemical impedance spectroscopy revealed that the CNS@Si–GQDs (7 ppm) electrode possessed the lowest charge-transfer resistance (Rct = 241.62 Ω cm2), significantly lower than those of the 3 ppm and 5 ppm electrodes, indicating enhanced interfacial electron-transfer kinetics and catalytic activity. Tafel polarization analysis further confirmed improved exchange current density and faster triiodide reduction kinetics after GQD incorporation. The enhanced electrochemical performance was attributed to the synergistic interaction between the conductive GQD network and the CNS@SiO₂ core–shell structure, which increased the electroactive surface area, promoted electron mobility, and provided abundant catalytic active sites. Additionally, the SiO₂ interfacial layer helped suppress charge recombination and stabilize the hierarchical nanostructure. This study demonstrates a scalable, low-cost, and efficient Pt-free strategy for next-generation DSSCs and provides insights into the design of advanced electrocatalysts for sustainable solar energy conversion.
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A novel of WS2–MoCuO3 supported with graphene quantum dot as counter electrode for dye-sensitized solar cells application
(2023-12-01)
Areerob, Yonrapach
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Oh, Won Chun
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Hamontree, Chaowalit
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Nachaithong, Theeranuch
;
Nijpanich, Supinya
A novel tungsten disulfide-molybdenum copper oxide composite supported with graphene quantum dots (WM@GQDs) has been synthesized as a counter electrode (CE) for dye-sensitized solar cells (DSSCs) using a simple and low-cost ultrasonication method. The unique structure of WM@GQDs exhibits excellent power conversion efficiency due to its high catalytic activity and charge transport properties. In addition, the graphene quantum dots (GQDs) provide more active sites in the zero-dimensional materials for an I/I<inf>3</inf>− redox reaction which can improve the electrical and optical properties of the composite. The results indicate that the amount of GQDs in the composite affect the effectiveness of solar devices. When 0.9%wt of GQDs was used, the WM@GQDs composite achieved an efficiency of 10.38%, which is higher than that of the expensive platinum CE under the same conditions. The mechanism behind the improved power conversion efficiency (PCE) of the composite sample is also discussed in detail. Therefore, WM@GQDs can be an efficient material to replace platinum in DSSCs as a CE.
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Synthesis of novel MoWO4 with ZnO nanoflowers on multi-walled carbon nanotubes for counter electrode application in dye-sensitized solar cells
(2022-12-01)
Areerob, Yonrapach
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Hamontree, Chaowalit
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Sricharoen, Phitchan
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Limchoowong, Nunticha
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Nijpanich, Supinya
Novel MoWO<inf>4</inf> with ZnO nanoflowers was synthesized on multi-walled carbon nanotubes (MW-Z@MWCNTs) through a simple hydrothermal method, and this unique structure was applied as a counter electrode (CE) for dye-sensitized solar cells (DSSC) for the first time. The synergetic effect of ZnO nanoflowers and MoWO<inf>4</inf> on MWCNTs was systematically investigated by different techniques. The amount of MWCNTs was optimized to achieve the best DSSC performance. It was found that the 1.5% MW-Z@MWCNTs composite structure had the highest power conversion efficiency of 9.96%, which is greater than that of traditional Pt CE. Therefore, MW-Z@MWCNTs-based CE can be used to replace traditional Pt-based electrodes in the future.
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Novel gamma-irradiated chitosan-doped reduced graphene-CuInS2 composites as counter electrodes for dye-sensitized solar cells
(2022-05-20)
Areerob, Yonrapach
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Hamontree, Chaowalit
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Sricharoen, Phitchan
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Limchoowong, Nunticha
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Laksee, Sakchai
To address the issues associated with traditional counter electrodes, a novel gamma-irradiated chitosan-doped reduced graphene-CuInS<inf>2</inf> composite (Chi@RGO-CIS) was used as the counter electrode (CE). The system was fabricated following a simple hydrothermal method. The prepared Chi@RGO-CIS was characterized by various spectroscopic and microscopic techniques. The synergistic effect between chitosan, CuInS<inf>2</inf>, and reduced graphene oxide can help in producing a large surface area. It can also help in the generation of catalytic sites toward I-/I<inf>3</inf>-redox electrolytes. We used a composite (based on electrical considerations) to study the effect of the amount of graphene on the characteristics and photovoltaic efficiency of the Chi@RGO-CIS composites. The solar cell assembled with 1.5% Chi@RGO-CIS exhibited an efficiency of 12.21%. The efficiency was higher than that of a Pt-based device (9.96%) fabricated under the same conditions. Hence, Chi@RGO-CIS can be potentially used as the CE of dye-sensitized solar cells (DSSCs). It can be used as a substitute for Pt in DSSCs.
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Photocatalytic decolorization of ZnO/Fe for the removal of methylene blue by new microwave methodology
(2022-04-01)
Areerob, Yonrapach
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Oh, Won Chun
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Pattarith, Kongsak
The photocatalysis of ZnO/Fe was performed by the simple microwave method for the removal of methylene blue. All samples were found to possess a single-phase monoclinic scheelite structure. On loading 5.0 mol% of Fe to the samples, the photocatalytic activities were enhanced, suggesting the potential application of the material as a superior visible light-driven photocatalyst relative to pure ZnO for the decolorization of methylene blue dye. The enhanced decolorization activity of the photocatalyst demonstrated the ability of Fe to reduce the band gap energy of ZnO and improve the electron transfer in the ZnO/Fe adsorbent. Moreover, the ultraviolet–visible absorption experiments exhibited an excellent decolorization rate (30 min) along with a decolorization efficiency of 93% upon the UV irradiation of ZnO/Fe in the pH range. The possible reaction mechanism and decolorization pathway of the photocatalyst were discussed in detail, and the stability of the catalyst was confirmed by the reusability test.

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