Nizamudeen Cherupurakal

The development of sustainable, cost-effective, and high-performance counter electrodes (CEs) remains a major challenge in dye-sensitized solar cell (DSSC) research. Although Pt remains the benchmark CE because of its excellent electrocatalytic activity and electrical conductivity, its scarcity and high cost motivate the development of efficient Pt-free alternatives. Herein, we report a novel Pt-free counter electrode based on a MOF-derived ZnO/NiCo2O4/Nb2C MXene composite for DSSC applications. The counter electrode materials were synthesized by a hydrothermal method and systematically characterized to evaluate their structural, morphological, and photovoltaic properties. X-ray diffraction analysis revealed characteristic peaks at 36.3°, 34.1°, and 40.3°, confirming the formation of ZnO, NiCo2O4, and Nb2C. The optimized ZnO/NiCo2O4/Nb2C MXene counter electrode achieved a power conversion efficiency (PCE) of 8.08%, comparable to that of Pt-based DSSCs under standard illumination. This enhanced performance is attributed to the synergistic effects of high catalytic activity, rapid charge transfer, and robust structural integrity in the MOF-derived ZnO/NiCo2O4/Nb2C MXene composite. Also, the addition of Nb2C MXene significantly enhanced the overall electrical conductivity and accelerated electron transfer kinetics at the electrolyte–electrode interface. These findings demonstrate that the ZnO/NiCo2O4/Nb2C MXene composite is a promising platinum-free counter electrode for advancing DSSCs toward practical commercialization and large-scale energy harvesting applications.

Dye-sensitized solar cells (DSSCs) are low-cost solar energy conversion devices with variable color and transparency advantages. DSSCs' potential power efficiency output, even in diffuse light conditions with consistent performance, allows them to be used in building-integrated photovoltaics (BIPV) window applications. Significantly, the development of bifacial DSSCs is getting significant scientific consideration. Triiodide/iodide (I₃^–/I^–) redox couple-mediated DSSCs require highly effective and stable electrocatalysts for I₃⁻ reduction to overcome their performance constraints. However, the commonly employed platinum (Pt) cathodes have restrictions on high price and unfavorable durability. Here, we report platinum nanoparticles (Pt NPs) incorporated into multiwalled carbon nanotubes (MWCNT) composites with lower Pt content as an efficient bifacial counter electrode (CE) material for DSSC applications. Pt NPs were homogenously decorated over the MWCNT surfaces using a simple polyol method at relatively low temperatures. CEs fabricated using Pt/MWCNT composites exhibited excellent transparency and power conversion efficiencies (PCE) of 6.92% and 6.09% for front and rear illumination. The results are expected to bring significant advances in bifacial DSSCs for real-world window applications.

The enduring effort toward stabilizing and improving the efficiency of dye-sensitized solar cells (DSSCs) has stirred the solar research community to follow innovative approaches. Current research centered on electrode materials design, which improves photoanodes' light-harvesting efficiency (LHE). Metal–Organic Frameworks (MOFs) are a new family of materials that can be used as competent materials due to their desirable qualities, including high porosity, flexible synthesis methodology, high thermal and chemical stability, and good light-harvesting capabilities. MOF-derived porous photoanodes can effectively adsorb dye molecules and improve LHE, resulting in high power conversion efficiency (PCE). Doping is a prospective methodology to tune the bandgap and broaden spectral absorption. Hence, a novel and cost-effective synthesis of high surface area transition metal (TM) doped TiO₂nanocrystals (NCs) via the metal–organic framework route for DSSCs is reported here. Among the TM dopants (i.e., Mn, Fe, Ni), a remarkable PCE of 7.03% was obtained for nickel-doped samples with increased Jsc (14.66 mA/cm²) due to the bandgap narrowing and porous morphology of TiO₂. The findings were further confirmed using electrochemical impedance spectroscopy (EIS) and dye-desorption experiments. The present study expedites a promising way to enhance the LHE for many innovative optoelectronic devices.

Summary: In recent years, there has been much focus on how the structure and morphology of CoMn₂O₄ materials influence their electrochemical performance. Herein we introduce a KOH‐surfactant agent to form a hexagonal like‐CoMn₂O₄ via hydrothermal. The X‐ray Rietveld refinement evidenced that spinel CoMn₂O₄ with the tetragonal structured I 41/amd phase. Further, the chemical environment of this phase is identified using various techniques. Surface morphology studies revealed hexagonal‐like features. Owing to its features, the material delivers an excellent capacitance of 638.8 F/g. CoMn₂O₄ also shows attained columbic efficiency of 81% and retains a capacitance of 85% after 4000 charge‐discharge cycles. The excellent cyclic stability and high performance are achieved due to the more active sites and convenient electronic transference route for the ions through an electrochemical process. The symmetrical two‐electrode assembly has also been fabricated. Hence, we believed that the surfactant‐KOH mediated hexagonal‐like‐CoMn₂O₄ material should enhance the supercapacitor properties.