Preparation of nano silver pastes applied in printed electronics

Printed electronics have become research focus due to their distinct characteristics such as tiny, flexible, thin, and easy to carry. Printed electronics have shown great potential in daily use, such as RFID tags, smart cards and displays. Silver nanoparticles have been applied as conductors in printed electronics. Different kinds of chemicals are used as solvent and stabilizers to prepare nano silver pastes in the paper. Silver nanoparticles are well distributed in the chemicals by ultrasonic method. The nano silver pastes are deposited on glass slides. Nano silver pastes are annealed at certain temperature to thermally decompose the stabilizers and solvent. The resultant nano silver films are sintered and highly conductive. The resistivity of conductive silver films prepared by using lactic acid and ethylene glycol was 2.6 × 10^-5 Ω·cm after annealing at 200°C for 30 min, and the resistivity was 6.4 × 10^-6 Ω·cm when the silver conductive films was annealed at 250°C. The microstructures of conductive lines formed by this method are investigated by SEM and SPM.