Morphological Regulation of Printed Low-Temperature Conductive Ink

Abstract

The unbalanced evaporation of solvents in lowtemperature sintered inks for printed electronics leads to a series of problems in the actual printing process, including printed pattern distortion, surface cracking, and the coffee ring effect, which has become a serious obstacle to this technique. Here, we present a comprehensive investigation of the influence of the solvent composition, environmental, and sintering conditions on the complicated pattern formation process of reactive silver inks. The results first showed that only inks with a certain wettability of solvents could form well-defined patterns. Then, the solvent composition and ambient humidity can be adjusted to balance the nonequilibrium evaporative flow within the liquid and thus to obtain a flat liquid film. Combined with the rapid UV sintering process, the particle size, porosity, and roughness could be controlled to produce dense and homogeneous silver films. Finally, we successfully printed silver electrodes with a smooth and dense surface (R qs ∼ 21 nm in 0.8 × 0.8 mm 2 area and less than 1% porosity) under an optimized relative humidity (RH) of 50−60% at room temperature with the solvent composition of IPA (isopropanol)/2,3-BD (2,3-butanediol) = 8:2. In addition, we also demonstrated high-performance Pr−IZO (praseodymium-doped indium−zinc oxide) thin film transistors (TFTs) with a mobility (μ sat ) of 2.14 cm 2 /V/s and I on /I off ratio of over 10 7 using source−drain electrodes printed under optimized conditions.

Investigation of Reactive Silver Ink Formula for Reduced Silver Consumption in Silicon Heterojunction Metallization

“…Printing 3.1 μΩ·cm silver films at 61 °C substrate temperatures with no post-processing is a state-of-the-art result. Of the many reports on reactive silver inks, only a few show lower resistivities (Table S6), and none match our low-temperature performance (<65 °C). ,,− …”

Inkjet Printing Optimization: Toward Realization of High‐Resolution Printed Electronics

“…[55][56][57] In addition, prior studies have successfully demonstrated the effectiveness of using co-solvents, which combine both low and high-boiling point solvents to suppress the evaporation rate of conductive inks. [58,59] Harmonious interplay of ethylamine and ethanolamine as solvents in the particle-free Ag ink has been substantiated by the extended operational lifespan of all nozzles, allowing printing delays of up to 90 min without any sign of clogging or performance degradation. [46] In addition to maintaining a smooth jetting, the combination of dimethylformamide, mono-ethylene glycol, and water has proven effective in addressing other additional issues, such as satellite droplets, poor wettability, and coffee ring effect-among the challenges encountered by the ink when using either one of the solvents.…”

The Synthesis of Copper Nanoparticles for Printed Electronic Materials Using Liquid Phase Reduction Method

“…In the field of conductive inks, nano-metallic conductive inks have attracted widespread attention due to their excellent electrical conductivity, low sintering temperatures, and good flexibility [8][9][10]. Gold and silver nanoparticles were the focus of early research, but their high cost limits large-scale application [11][12][13].…”