Particle-free gold metal–organic decomposition ink for inkjet printing of gold structures

Abstract The application of liquid [AuO2CCH2(OCH2CH2)2OCH3(nBu3P)] (1) as a metal–organic decomposition ink containing 34.2 wt.% of gold is reported. Chemical and physical properties of 1 are discussed. The ink formulated of 20 wt.% of 1 in toluene (gold concentration 6.9 wt.%) exhibits rheological properties well-suited for piezo inkjet printing. Conversion into electrically conductive gold was accomplished by thermal treatment optimized to provide best possible conductivity, contour accuracy, and layer homogeneity. The thermal decomposition of 1 was studied by thermogravimetry–mass spectrometry coupling experiments. It was found that at first decarboxylation takes place forming [AuCH2(OCH2CH2)2OCH3(PnBu3)], further heating cleaves the Au P bond and releases PnBu3. This resulting compound decomposes via Au C, C C and C O bond cleavage processes giving gold and appropriate organics (CxHyOz (x ≥ 3)). The printed features exhibit conductivities of up to 1.9 × 107 S·m− 1 on glass which corresponds to 43% of bulk gold conductivity.