Preparation of Conductive Nanoink Using Pulsed-Wire-Evaporated Copper Nanoparticles for Inkjet Printing

Pulsed-wire evaporation (PWE) was used to synthesize copper nanoparticles having an average diameter of about 100 nm. These were coated with 1-octanethiol (CH3(CH2)(7)SH) under high vacuum (HV) (5.33 x 10(-4) Pa) using vapor self-assembled multilayers (SAMs) to prevent oxidation of the nanoparticles. Conductive nanoink made from the coated nanoparticles was printed on glass. The printed patterns were sintered in hydrogen (99.999 vol%) and mixed gas (Ar 95 vol% H-2 5 vol%) atmospheres; a high copper line density was achieved. Differential scanning calorimetry (DSC) established that the removal temperature of 1-octanethiol was 143 degrees C, well below the 350 degrees C sintering temperature. Complete removal of 1-octanethiol after sintering was confirmed by X-ray photoelectron spectroscopy (XPS). The resistivity of the hydrogen-sintered copper sample was 1.74 x 10(-7) Omega.m. This dry powder fabrication and coating method is an alternative approach to inhibit copper oxidation and form inkjet-printed lines. [doi: 10.2320/matertrans.M2012137]This work was carried out with the support of a Next Generation New Technology Development Program (Project No. 10030038) of the Korean Ministry of Commerce, Industry, and Energy (MOCIE). This work was also supported by the Human Resources Development of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Ministry of Knowledge Economy, Republic of Korea (No. 2010-4010100620) and by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (No. 2011-0029862). The authors would like to thank Dr. Young-suk Kim at KETI for his support