Structure–Defect–Interface Correlations in Cs x WO 3 /MWCNT Nanocomposites: Implications for Broadband NIR Absorption and Photothermal Behavior

High Resolution Image Download MS PowerPoint Slide Cs x WO 3 /multiwalled carbon nanotube (MWCNT) nanocomposites were synthesized via a time-controlled solvothermal process to investigate how synthesis duration influences crystallinity, oxygen-related structural features, and oxide–carbon interfacial characteristics. Structural and spectroscopic analyses indicate that lattice ordering and defect-associated features evolve systematically with the reaction time, while MWCNTs serve as conductive scaffolds that promote dispersion, thermal transport, and interfacial coupling. Optical and thermal measurements reveal a clear correlation between oxygen-related states and photothermal behavior. The composites exhibit broad UV–Vis–NIR absorption, which is discussed in terms of localized surface plasmon resonance (LSPR), polaronic transitions, and interfacial interactions. Under NIR irradiation (0.8 W cm –2 for 300 s), surface temperatures of up to ∼112 °C were achieved, reflecting efficient light-to-heat conversion under concentrated illumination. Overall, this study provides qualitative insight into how the synthesis duration mediates the interplay between structural order, oxygen-related features, and photothermal response in Cs x WO 3 /MWCNT hybrids, offering guidance for the rational design of oxide–carbon photothermal materials.