Sonication-assisted layer-by-layer deposition of gold nanoparticles for highly conductive gold patterns

Sonication-assisted layer-by-layer (LBL) deposition of gold nanoparticles (GNPs) was carried out in an attempt to prepare highly conductive gold patterns on polyimide substrates. First, sonication time was optimized with GNPs (12.8 nm) whose size was large enough to be analyzed by FE-SEM in order to evaluate the surface coverage. Next, multilayer formation (4, 8 and 12 layer) was confirmed using ethanedithiol (EDT) as linker molecules under optimized conditions by measuring their UV absorption, near-IR (NIR) transmittance, thickness, and electrical conductivity. Finally, 20-layer films using small GNPs (2.5 nm) were prepared with or without patterning, followed by sintering at 150 °C for 1 h, which provided clean gold patterns with high electrical conductivity (2.5 × 105 Ω−1 cm−1).

► We have introduced sonication-assisted LBL deposition of GNPs for the first time.
► This resulted in very high electrical conductivity of GNP layer (2.5 × 105 Ω−1 m−1).
► It also shortened deposition time to ∼10 min per layer compared with ∼60 min by the conventional LBL deposition.
► This also provided clean gold patterns on polyimide.