The impact of solvent characteristics on performance and process stability of printed carbon resistive materials

Abstract

Carbon conductive pastes deposited by screen printing are used in many commercial applications including sensors, PCB, batteries, and PV, and as such represent an important value-added coating. An experimental investigation was carried out into the role of the solvent on the drying characteristics, conductivity, and process consistency in screen printed carbon pastes. Four materials with solvent boiling points between 166 and 219°C were deposited at film thickness between 6 and 16 lm, and the sheet resistance and film thickness were measured after successive passes through an industrial dryer operating with an air temperature of 155°C. Sheet resistances of 14 X/sq. were obtained with the thicker films while thinner films produced a sheet resistance of 46 X/sq. Thinner films achieved a stable resistivity within a 2.5-min residence time, while the thicker films required a residence time in excess of 12.5 min to achieve a stable resistivity. As well as prolonging drying times, the higher boiling point increased the resistivity of the cured film. It is postulated that the lower resistance of the faster drying materials is a result of film stressing increasing inter particle contact. Process models indicate that multiple thin layers are a more efficient means of manufacture for the process parameters examined.

High-speed imaging the effect of snap-off distance and squeegee speed on the ink transfer mechanism of screen-printed carbon pastes

“…Research has been conducted to identify the effects of various press parameter settings as well as ink formulation on screen-printed carbon inks and pastes to optimize print quality and electrical performance. 1,8,9 The effect of mesh material and geometry was found to be relatively consistent for a range of inks, with finer meshes leading to reduced film thickness but improved definition, which is preferable for fine feature printing. [9][10][11] Parameters such as squeegee hardness, angle, and geometry have also been found to have consistent effects on a range of inks, where softer squeegees at shallow angles were found to produce thicker deposits.…”

“…1,8,9 The effect of mesh material and geometry was found to be relatively consistent for a range of inks, with finer meshes leading to reduced film thickness but improved definition, which is preferable for fine feature printing. [9][10][11] Parameters such as squeegee hardness, angle, and geometry have also been found to have consistent effects on a range of inks, where softer squeegees at shallow angles were found to produce thicker deposits. 12 However, squeegee pressure, snap-off distance (the distance between the screen and the substrate) and print speed have not demonstrated consistent trends and have been shown to vary with the rheology of the ink.…”

Geometrical optimization for high efficiency carbon perovskite modules

“…The mesoporous zirconia layer was screen printed and heat treated at 400 °C for 30 minutes. The carbon was then screen printed with a D3 paste manufactured by Gwent Electronic Materials which was found to provide optimum high conductivity and process-ability (Philip et al, 2016). The layer was first dried at 100 °C then heat treated at 400 °C to create the porous structure.…”

Effect of photonic flash annealing with subsequent compression rolling on the topography, microstructure and electrical performance of carbon-based inks

“…Screen-printed carbon-based pastes and inks are extensively used in a wide range of printed electronics applications including resistive heater panels [1][2][3], electrochemical sensors [4,5] pressure sensors [6], printed batteries [7] and supercapacitors [8] as well as photovoltaic applications including perovskite and dye-sensitised solar cells [9][10][11][12].…”