Copper carboxylate with different carbon chain lengths as metal–organic decomposition ink

Abstract

The copper carboxylates with different carbon chain length (glycolate, lactate and oleate) were used to prepare the metal–organic decomposition ink. TG–MS showed that copper carboxylates underwent a two-step thermal decomposition for the conversion to elemental copper, and the organic residues after decomposition is relevant with the carbon chain length. Conductive copper films were obtained by drop coating of a copper carboxylate solution onto a glass slide followed by sintering at different temperatures. Copper carboxylates with shorter carbon chain give better conductive films. Both copper glycolate and copper lactate films begin to show conductivity after sintered at 150 °C for 60 min under nitrogen. The resistivity of the copper features with 2 μm thickness of copper glycolate and copper lactate was 23.0 ± 2 and 44.0 ± 6 μΩ cm after sintering at 250 °C for 60 min under nitrogen, respectively, with the former being about 7.4 % of the conductivity of bulk copper. X-ray photoelectron spectroscopy results showed slight surface oxidation in the sintered copper feature from these copper carboxylates. Although the conductivity of the obtained copper film needs to be improved further, the method shows some advantages over the copper nanoparticles ink, such as avoiding tedious synthesis and protection of nanoparticles, low cost, etc.