Flash light sintered copper precursor/nanoparticle pattern with high electrical conductivity and low porosity for printed electronics

• The hybrid copper inks with precursor and nanoparticles were fabricated.
• The hybrid copper ink was sintered via flash light irradiation.
• The resistivity of sintered hybrid copper ink was 27.3 μΩ cm.
• Highly conductive copper film with low porosity could be achieved.

In this work, the hybrid copper inks with precursor and nanoparticles were fabricated and sintered via flash light irradiation to achieve highly conductive electrode pattern with low porosity. The hybrid copper ink was made of copper nanoparticles and various copper precursors (e.g., copper(II) chloride, copper(II) nitrate trihydrate, copper(II) sulfate pentahydrate and copper(II) trifluoroacetylacetonate). The printed hybrid copper inks were sintered at room temperature and under ambient conditions using an in-house flash light sintering system. The effects of copper precursor weight fraction and the flash light irradiation conditions (light energy and pulse duration) were investigated. Surfaces of the sintered hybrid copper patterns were analyzed using a scanning electron microscope. Also, spectroscopic characterization techniques such as Fourier transform infrared spectroscopy and X-ray diffraction were used to investigate the crystal phases of the flash light sintered copper precursors. High conductivity hybrid copper patterns (27.3 μΩ cm), which is comparable to the resistivity of bulk copper (1.68 μΩ cm) were obtained through flash light sintering at room temperature and under ambient conditions.