Inkjet Printed Strain Gauges Fabricated Using AgNO₃/Ethylene Glycol-Based Inks

The Influence of Microstructure on TCR for Inkjet-Printed Resistive Temperature Detectors Fabricated Using AgNO3/Ethylene-Glycol-Based Inks

“…For sensors printed using the tri-EG ink, the resistance decreased linearly with increasing plasma exposure from an average of ~244 Ω at 15 min to ~63 Ω at 30 min. These results are consistent with the sheet resistance measurements for strain gauges made using mono-EG, di-EG, and tri-EG inks reported previously [ 10 ]. For RTDs made using the di-EG and tri-EG inks, plasma exposure times less than 15 min resulted in structures with resistances that exceeded the measurement range of the multimeter (100 MΩ) and, thus, were excluded from further study.…”

“…Plasma exposure times ranged from 4 to 30 min in order to explore the effect of plasma exposure on sensor performance. A power of 300 W was selected for samples printed using the di-EG and tri-EG inks because previous work showed that a power of 150 W was insufficient to create structures with measurable electrical resistance even after 20 min of plasma exposure [ 10 , 13 ]. A power of 150 W was used for samples printed using mono-EG inks because previous work showed that 200 W produced structures with maximum conductivity in less than 15 min [ 11 ], which, for this study, was deemed too short to tune the resistance of printed structures using plasma exposure time as a control parameter.…”

“…This process utilizes a low-pressure Ar plasma to form conductive Ag structures from particle-free inks comprised of silver nitrate (AgNO 3 ) as the precursor and ethylene glycol as the ink solvent. During Ar plasma treatment, the substrate temperature is between ~39 °C and ~140 °C, depending on power and treatment time [ 9 , 10 ]. Such low substrate temperatures enable the fabrication of Ag devices on temperature-sensitive substrates, such as paper and cellophane.…”

“…Such low substrate temperatures enable the fabrication of Ag devices on temperature-sensitive substrates, such as paper and cellophane. We have successfully used this approach to fabricate a wide range of Ag-based devices and sensors, including RC filters [ 11 ], RTDs [ 12 ], strain gauges [ 10 ], and chemical sensors [ 13 ]. For strain gauges, we found that the gauge factor exhibits a strong dependence on the microstructure of printed structures, which, in turn, depends on whether monoethylene glycol (mono-EG) or one of its derivatives, namely diethylene glycol (di-EG) or triethylene glycol (tri-EG), is used as the ink solvent.…”

Fabrication of RC filters from a single printed Zn layer by reactive inkjet printing

“…For example, resistors have been printed using a silver nitrate-based precursor ink and an ascorbic acidbased reducing agent by printing the precursor ink and reducing agent separately in different sequences to achieve resistivities that vary by over four orders of magnitude [19]. Likewise, resistors have been formed using plasma reduction of a silver nitrate precursor ink using plasma treatment duration and plasma power to vary the resistivity by over six orders of magnitude [20]. To the best of our knowledge, a printing-only process capable of producing both high resistance and low resistance structures side-by-side in a single printed layer has yet to be developed.…”