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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
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Wannabut, Wassana
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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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Design and Implementation of a High-Field NdFeB Magnet System for Investigating the Spin Seebeck Effect
(2025-01-01)
Nachaithong, Theeranuch
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Wongjom, Chalothon
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Samransuksamer, Benjarong
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Phumying, Santi
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Pongophas, Ekkarat
The generation of pure spin current through thermal gradients, known as the spin Seebeck effect (SSE), has garnered significant interest in spintronics. In this study, we design and construct a permanent magnetic instrument setup to generate a variable external magnetic field using NdFeB permanent magnets to observe the SSE. The experimental setup is composed of three crucial components: the magnetic field, the temperature gradient, and electronic control systems. Si/yttrium iron garnet (YIG)/platinum (Pt) and Si/nickel (Ni) samples, prepared via sputtering techniques, were utilized for standard calibration purposes. The results show that the external magnetic field produced by NdFeB varies with the gap distance between the two magnetic poles, following an exponential decrease in field strength with increasing gap distance. The magnetic field at the center can be adjusted from ±20 to ±5000 Oe. The temperature gradient stabilizes after approximately 10 min, with a temperature difference ( ΔT ) between the heated and cooled sides ranging from 0 to 30 K. For instrument testing, we performed magnetic field and angle-dependent measurements on Si/YIG/Pt and Si/Ni samples. The results indicate that the magnetic field dependence of the permanent magnet instrument (PMI) does not exhibit the voltage loop switching seen with an alternative magnetic coil (AMC) but shows analogous behavior at high magnetic fields. Moreover, the angle dependence of both PMI and AMC yielded comparable results. In conclusion, our PMI setup procedures effectively facilitate the observation of the SSE.
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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
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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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