Dimension-dependent electron-phonon interactions in silver nanomaterials for high-efficiency electrothermal conversion

Flexible electric heaters require materials with precise temperature control and rapid thermal response capabilities. In this work, we systematically investigate the influence of material dimensionality and nanoparticle deposition density on electrothermal conversion in silver nanomaterials. We found that variations in the contact modes among zero-dimensional (0D) silver nanoparticles significantly affect their electrothermal performance. Specifically, a lower deposition density results in relatively slender sintering necks, which enhance electron-phonon interactions and localized Joule heating effects, thus improving the electrothermal conversion efficiency. In contrast, a higher deposition density leads to more robust and thicker sintering necks, which reduces efficiency. Extending the study to one-dimensional (1D) silver nanowires, quasi-two-dimensional (quasi-2D) silver flakes, and three-dimensional (3D) silver films, comparative analyses reveal a clear dimension-dependent hierarchy, with the order of electrothermal conversion efficiency being 0D > 1D > quasi-2D > 3D. As a demonstration, the fabricated Ag NPs/PI heater ( R s ∼3 Ω/sq, 2 cm × 2 cm) exhibits superior performance, with a rapid thermal response (∼250°C within 10 s), stable low-voltage operation (< 5 V), and high-temperature stability (∼250°C). This dimensional comparison reveals fundamental correlations between nanomaterial structure and electrothermal performance, establishing design principles for next-generation flexible heating systems.