.

1. A Water-Based Inkjet Printable Silver Conductive Ink:
Synthesis, Characterization and Printability
Aiman Sajidah Abd Aziz1*,
Siti Zuulaika Rejal1
,Syed Muhammad Hafiz1
, Nora’zah
Abdul Rashid1
, Suraya Sulaiman1
.
1
Flexible Electronics Lab, Research and Development, Corporate Technology, MIMOS Berhad,
Technology Park Malaysia, Kuala Lumpur, Malaysia.
*Corresponding author’s phone: +603-8995 5000
E-mail: aiman.aziz@mimos.my
ABSTRACT
In this study, we investigated the
physico-chemicaland printability
properties of a water-based inkjet printable
silver conductive ink. The inks contain
silver nanoparticles with a mean diameter
of less than 20nm were synthesized by a
chemical reduction process comprising a
certainratiometric of silver colloid in water
and dispersants. The as-prepared silver
conductive ink has been successfully
tailored and employed to fabricate
conductive patterns on polyethylene
terephthalate (PET) flexible substrate via
the inkjet printing method. The resulting
conductive ink is homogeneously
dispersed in water and can be stored for
several months.In addition, the printed
patterns have demonstrated high
conductivity of 104
S/cm. Finally, the
developed water-based silver inkjet ink has
been successfully printed for various
electronics patterns in developing next-
generation flexible printed electronics
applications.
Keywords—silvernanoparticle;
conductive ink; flexible electronics;
chemical reduction; inkjet printing
1.0 INTRODUCTION
Nanoparticle application in
conductive ink is one of the promising
applications in electronics technology that
is due to its capability to enhance
performance. Several studies have been
carried out by researchers to formulate the
conductive ink by suspended particles in
water or organic solvents, such as toluene,
glycols or cyclohexane to produce non-
agglomerated particles [1-3].
Generally, metal nanoparticles can
be prepared by physical and chemical
methods. The chemical reduction method
offers great advantages including simple
production, convenient operation and the
low price of raw materials [5]. Silver
nanoparticles (AgNPs) have unique
physical and chemical properties such as
high electrical and thermal conductivity,
chemical stability, relatively low cost,
resonant, moldable, malleable and the
ability of its oxide form to conduct
electricity. Additionally, silver
nanoparticles have a low melting point,
which supports the generation of
conductive thin filmsthat is much likely
suitable for application in flexible
electronics [1,4,6].
Inkjet printing technology has been
investigated as an alternative production
tool for the fabrication of conductive
patterns and devices in the field of flexible
electronics [1]. During the inkjet printing
process, typically the solvent evaporates
simultaneously in the nozzle during the ink
deposition hence it will hinder the ejection
of the fluid [7]. Therefore, ink formulation
is very important in inkjet technology. In
this study, we will discuss the physico-
chemicaland printability properties of a
water-based inkjet printable silver
conductive ink.
Proceedings of the 4th International Symposium on Advanced Materials and Nanotechnology 2020
(i-SAMN2020), December 1-3, 2020
127

2. 2.0 THEORY/LITERATURE
REVIEW
In this research work, we have
studied the process to produce silver
nanoparticles from bottom-up nanoparticle
growth process and ink formulations
towards application in inkjet ink for
various electronics printing.
3.0 MATERIALS
All the chemicals purchased were
of analytical grade and used without
further purification. Silver nitrate
(AgNO3), reducing agent, humectant and
solvents were obtained from Sigma
Aldrich, USA and Merck, Germany.
4.0 EXPERIMENTAL
4.1 Synthesis of Silver Nanoparticles
In this study, AgNPs were
synthesised via the chemical reduction
method. AgNO3 was dissolved in water
and mixed with a precipitant reducing
agent. The solution was stirred in order to
promote the nucleation and growth of
AgNPs. The excess of unreacted material
was washed several times with an organic
solvent and further purified using a
centrifuge. Sedimentary solid particles
were recovered by decantation. Then, the
collected solid was further dispersed in
deionized water to form a silver colloid
which was further mixed with certain
ratiometric of dispersants to produce inkjet
silver conductive inks.
4.2 Inkjet Printing
The prepared conductive inks were
used for printing using an inkjet printer
FUJIFILM Dimatix DMP 2850. Initially,
the ink was filtered and injected into
piezoelectric inkjet cartridges with 16
nozzle heads. The desired conductive
patterns were printed on a flexible PET
substrate.
4.3 Characterization of Silver
Nanoparticles
The morphology analysis of
AgNPs were performed by transmission
electron microscopy (TEM) and field
emission scanning electron microscopy
(FESEM). The ink surface tension was
characterized using the drop shape
analyzer DSA253, Kruss GmbH and the
viscosity was measured using a
Viscometer SV-1A. The electrical
properties of the printed ink were
measured by a four-point probe using a
resistivity meter (Loresta-GX MCP-T700).
5.0 RESULTS AND DISCUSSION
5.1 The Morphology Study of Silver
Conductive Ink
Based on the analysis presented in
Fig. 1(a), it was observed that the
synthesized AgNP nanoparticles are at the
nanometer-sized and spherical shape.
Meanwhile, the mean diameter of the
silver nanoparticles obtained was 9nm.
The analogous observation was described
in the previous report where by the
obtained AgNPs mean diameter is in the
range of 5 to 40nm [8]. Fig. 1(b) shows
that the synthesized AgNP has an arrow
distribution of particle size in the range of
5 to 20nm. Therefore, the synthesized
AgNPs are in a desirable particle size
range suitable for inkjet printing
fabrication.
Fig. 1: (a) TEM image and (b) particlesize
distribution of the AgNPs.
5.2 The Physical Study of Silver
Conductive ink
In this work, we have prepared four
types of conductive inks. Silver
(a) (b)
128

3. nanoparticle conductive inks were
prepared with silver colloid in water and
mixed with dispersants of humectant and
solvent as tabulated in Table II. The ink
printability was found to be dependent on
the dispersants used.
TABLE II: Ink Formulation
Ink AgNPs in water: humectant:
solvent
A 64:18:18
B 78:12:10
C 71:16:13
D 94:4:2
Table III shows the effect of inks
and the influence of surface tension on the
inkjet printability. It is observed that the
surface tension increases with the
increasing amount of AgNPs in the water.
Ink D has the highest water content. This
is due to the high value of water surface
tensionof 72mN/m (at 20°C) in which
significantly affects the overall ink surface
tension. Based on Table III, the surface
tension of Ink A is low compared to other
inks, only 44.07 mN/m, due to high
organic solvent content. On the other hand,
Ink C has shown a low surface tension
value of 50.85 mN/m and a suitable value
for ink conductivity.
Meanwhile, the viscosity and
surface tension values of the samples are
within the satisfactory printable range for
inkjet devices.
TABLE III: Ink Viscosity and Surface
Tension
Ink Viscosity
(cP)
Surface tension
(mN/m)
A 5.68 44.07
B 8.44 43.00
C 8.31 50.85
D 8.10 59.84
5.3 Electrical Properties of Silver
Nanoparticles
As depicted in Fig. 2, the
formulated silver ink was fabricated into a
1cm2
design on PET flexible substrate.
The drop spacings (10, 15 and 20 μm)
were varied for each layer of ink. Fig. 3
shows a uniform and dense particle printed
on the substrate.
Fig. 2: 1cm2
printed of AgNPspattern.
Fig. 3: Surface morphology ofthe printed AgNPs
ink.
The formulated printing ink effects
with its electrical conductivity
performance have been investigated at
10µm drop spacing (Fig.4). From the
results, all the formulated inks have shown
high conductivity in the range of 2 to
8x104
S/cm, which is higher than the
conductivity reported by previous research
in the range of 2 to 4x104
S/cm[9]. The
conductivity of silver film increases
subsequently with the increase of the
printed layer. The optimum dispersant
ratio metricis obtained from Ink C, which
has high conductivity on both printing
layers and has a uniform coating on the
PET substrate without any ink
agglomeration.
Fig. 4:The effect of inks against its conductivity at
10um drop spacing.
nanoparticle conductive inks were
prepared with silver colloid in water and
mixed with dispersants of humectant and
solvent as tabulated in Table II. The ink
printability was found to be dependent on
the dispersants used.
TABLE II: Ink Formulation
Ink AgNPs in water: humectant:
solvent
A 64:18:18
B 78:12:10
C 71:16:13
D 94:4:2
Table III shows the effect of inks
and the influence of surface tension on the
inkjet printability. It is observed that the
surface tension increases with the
increasing amount of AgNPs in the water.
Ink D has the highest water content. This
is due to the high value of water surface
tensionof 72mN/m (at 20°C) in which
significantly affects the overall ink surface
tension. Based on Table III, the surface
tension of Ink A is low compared to other
inks, only 44.07 mN/m, due to high
organic solvent content. On the other hand,
Ink C has shown a low surface tension
value of 50.85 mN/m and a suitable value
for ink conductivity.
Meanwhile, the viscosity and
surface tension values of the samples are
within the satisfactory printable range for
inkjet devices.
TABLE III: Ink Viscosity and Surface
Tension
Ink Viscosity
(cP)
Surface tension
(mN/m)
A 5.68 44.07
B 8.44 43.00
C 8.31 50.85
D 8.10 59.84
5.3 Electrical Properties of Silver
Nanoparticles
As depicted in Fig. 2, the
formulated silver ink was fabricated into a
1cm2
design on PET flexible substrate.
The drop spacings (10, 15 and 20 μm)
were varied for each layer of ink. Fig. 3
shows a uniform and dense particle printed
on the substrate.
Fig. 2: 1cm2
printed of AgNPspattern.
Fig. 3: Surface morphology ofthe printed AgNPs
ink.
The formulated printing ink effects
with its electrical conductivity
performance have been investigated at
10µm drop spacing (Fig.4). From the
results, all the formulated inks have shown
high conductivity in the range of 2 to
8x104
S/cm, which is higher than the
conductivity reported by previous research
in the range of 2 to 4x104
S/cm[9]. The
conductivity of silver film increases
subsequently with the increase of the
printed layer. The optimum dispersant
ratio metricis obtained from Ink C, which
has high conductivity on both printing
layers and has a uniform coating on the
PET substrate without any ink
agglomeration.
Fig. 4:The effect of inks against its conductivity at
10um drop spacing.
0
2
4
6
8
10
A B
Conductivity
x10⁴
(S/cm)
Ink
Single layer
Double layer
nanoparticle conductive inks were
prepared with silver colloid in water and
mixed with dispersants of humectant and
solvent as tabulated in Table II. The ink
printability was found to be dependent on
the dispersants used.
TABLE II: Ink Formulation
Ink AgNPs in water: humectant:
solvent
A 64:18:18
B 78:12:10
C 71:16:13
D 94:4:2
Table III shows the effect of inks
and the influence of surface tension on the
inkjet printability. It is observed that the
surface tension increases with the
increasing amount of AgNPs in the water.
Ink D has the highest water content. This
is due to the high value of water surface
tensionof 72mN/m (at 20°C) in which
significantly affects the overall ink surface
tension. Based on Table III, the surface
tension of Ink A is low compared to other
inks, only 44.07 mN/m, due to high
organic solvent content. On the other hand,
Ink C has shown a low surface tension
value of 50.85 mN/m and a suitable value
for ink conductivity.
Meanwhile, the viscosity and
surface tension values of the samples are
within the satisfactory printable range for
inkjet devices.
TABLE III: Ink Viscosity and Surface
Tension
Ink Viscosity
(cP)
Surface tension
(mN/m)
A 5.68 44.07
B 8.44 43.00
C 8.31 50.85
D 8.10 59.84
5.3 Electrical Properties of Silver
Nanoparticles
As depicted in Fig. 2, the
formulated silver ink was fabricated into a
1cm2
design on PET flexible substrate.
The drop spacings (10, 15 and 20 μm)
were varied for each layer of ink. Fig. 3
shows a uniform and dense particle printed
on the substrate.
Fig. 2: 1cm2
printed of AgNPspattern.
Fig. 3: Surface morphology ofthe printed AgNPs
ink.
The formulated printing ink effects
with its electrical conductivity
performance have been investigated at
10µm drop spacing (Fig.4). From the
results, all the formulated inks have shown
high conductivity in the range of 2 to
8x104
S/cm, which is higher than the
conductivity reported by previous research
in the range of 2 to 4x104
S/cm[9]. The
conductivity of silver film increases
subsequently with the increase of the
printed layer. The optimum dispersant
ratio metricis obtained from Ink C, which
has high conductivity on both printing
layers and has a uniform coating on the
PET substrate without any ink
agglomeration.
Fig. 4:The effect of inks against its conductivity at
10um drop spacing.
B C D
Ink
Single layer
Double layer
129

4. Fig. 5: Printed (a) Interdigitated sensor platform
and (b) RFID antenna.
As shown in Fig. 5, the formulated
Ink C was further used for the
development of printed digital electronics
products. We have successfully printed the
interdigitated sensor platform for humidity
level determination and RFID antenna as a
preliminary proof of concept.
6.0 CONCLUSION
Silver is one of the potential
materials widely used in the production of
inkjet printable conductive ink. A simple
and rapid synthesis method to produce
water-based silver conductive ink with
AgNPs dispersion and narrow particle size
distribution is obtained. The best
formulation of conductive silver ink has
been realized and conductive devices have
been successfully fabricated on a flexible
substrate through the inkjet printing
method.
ACKNOWLEDGEMENTS
The research was supported by the
Ministry of Science, Technology and
Innovation (MOSTI) through the 11th
Malaysia Plan development expenditure
(DE) funding under P.300143 project. The
authors also thank MIMOS Berhad for
financial support and facilities.
REFERENCES
[1] C. Mau Dang, K. Kim Huynh, and D.
My Thi Dang, “Synthesis of Silver
Nanoparticles Using Poly(acrylic
acid) as a Capping Agent for
Conductive Ink in Inkjet Printing
Application,” Sci. Stay. True Here"
Biol. Chem. Res., vol. 6, p. 111, 2019.
[2] L. Ward, T. D. District, H. Chi, and
M. City, “Study of the formation of
silver nanoparticles and silver
nanoplates by chemical reduction
method Dung My `Thi Dang * and
Chien Mau Dang Eric Fribourg-
Blanc,” vol. 12, pp. 456–465, 2015.
[3] H. Lee, K. Chou, and K. Huang,
“Inkjet printing of nanosized silver
colloids,” vol. 2436, 2005.
[4] X. F. Zhang, Z. G. Liu, W. Shen, and
S. Gurunathan, “Silver nanoparticles:
Synthesis, characterization,
properties, applications, and
therapeutic approaches,” Int. J. Mol.
Sci., vol. 17, no. 9, 2016.
[5] G. Suriati, M. Mariatti, and A.
Azizan, “Synthesis of silver
nanoparticles by chemical reduction
method: effect of reducing agent and
surfactant concentration,” Int. J.
Automot. Mech. Eng., vol. ISSN, pp.
1920–1927, 2014.
[6] L. Cao et al., “The preparation of Ag
nanoparticle and ink used for inkjet
printing of paper based conductive
patterns,” Materials (Basel)., vol. 10,
no. 9, Aug. 2017.
[7] A. Lee et al., “Optimization of
experimental parameters to supress
nozzle clogging in inkjet printing,”
Ind. Eng. Chem. Res., vol. 51, no. 40,
Aug. 2012.
[8] M. Chien Dang, T. M. Dung Dang,
and E. Fribourg-Blanc, “Silver
nanoparticles ink synthesis for
conductive patterns fabrication using
inkjet printing technology,” Adv. Nat.
Sci. Nanosci. Nanotechnol., vol. 6, no.
1, 2015.
[9] Y. Li, Y. Wu, and B. S. Ong, “Facile
synthesis of silver nanoparticles
useful for fabrication of high-
conductivity elements for printed
electronics,” J. Am. Chem. Soc., vol.
127, no. 10, pp. 3266–3267, 2005.ao
Fig. 5: Printed (a) Interdigitated sensor platform
and (b) RFID antenna.
As shown in Fig. 5, the formulated
Ink C was further used for the
development of printed digital electronics
products. We have successfully printed the
interdigitated sensor platform for humidity
level determination and RFID antenna as a
preliminary proof of concept.
6.0 CONCLUSION
Silver is one of the potential
materials widely used in the production of
inkjet printable conductive ink. A simple
and rapid synthesis method to produce
water-based silver conductive ink with
AgNPs dispersion and narrow particle size
distribution is obtained. The best
formulation of conductive silver ink has
been realized and conductive devices have
been successfully fabricated on a flexible
substrate through the inkjet printing
method.
ACKNOWLEDGEMENTS
The research was supported by the
Ministry of Science, Technology and
Innovation (MOSTI) through the 11th
Malaysia Plan development expenditure
(DE) funding under P.300143 project. The
authors also thank MIMOS Berhad for
financial support and facilities.
REFERENCES
[1] C. Mau Dang, K. Kim Huynh, and D.
My Thi Dang, “Synthesis of Silver
Nanoparticles Using Poly(acrylic
acid) as a Capping Agent for
Conductive Ink in Inkjet Printing
Application,” Sci. Stay. True Here"
Biol. Chem. Res., vol. 6, p. 111, 2019.
[2] L. Ward, T. D. District, H. Chi, and
M. City, “Study of the formation of
silver nanoparticles and silver
nanoplates by chemical reduction
method Dung My `Thi Dang * and
Chien Mau Dang Eric Fribourg-
Blanc,” vol. 12, pp. 456–465, 2015.
[3] H. Lee, K. Chou, and K. Huang,
“Inkjet printing of nanosized silver
colloids,” vol. 2436, 2005.
[4] X. F. Zhang, Z. G. Liu, W. Shen, and
S. Gurunathan, “Silver nanoparticles:
Synthesis, characterization,
properties, applications, and
therapeutic approaches,” Int. J. Mol.
Sci., vol. 17, no. 9, 2016.
[5] G. Suriati, M. Mariatti, and A.
Azizan, “Synthesis of silver
nanoparticles by chemical reduction
method: effect of reducing agent and
surfactant concentration,” Int. J.
Automot. Mech. Eng., vol. ISSN, pp.
1920–1927, 2014.
[6] L. Cao et al., “The preparation of Ag
nanoparticle and ink used for inkjet
printing of paper based conductive
patterns,” Materials (Basel)., vol. 10,
no. 9, Aug. 2017.
[7] A. Lee et al., “Optimization of
experimental parameters to supress
nozzle clogging in inkjet printing,”
Ind. Eng. Chem. Res., vol. 51, no. 40,
Aug. 2012.
[8] M. Chien Dang, T. M. Dung Dang,
and E. Fribourg-Blanc, “Silver
nanoparticles ink synthesis for
conductive patterns fabrication using
inkjet printing technology,” Adv. Nat.
Sci. Nanosci. Nanotechnol., vol. 6, no.
1, 2015.
[9] Y. Li, Y. Wu, and B. S. Ong, “Facile
synthesis of silver nanoparticles
useful for fabrication of high-
conductivity elements for printed
electronics,” J. Am. Chem. Soc., vol.
127, no. 10, pp. 3266–3267, 2005.ao
Fig. 5: Printed (a) Interdigitated sensor platform
and (b) RFID antenna.
As shown in Fig. 5, the formulated
Ink C was further used for the
development of printed digital electronics
products. We have successfully printed the
interdigitated sensor platform for humidity
level determination and RFID antenna as a
preliminary proof of concept.
6.0 CONCLUSION
Silver is one of the potential
materials widely used in the production of
inkjet printable conductive ink. A simple
and rapid synthesis method to produce
water-based silver conductive ink with
AgNPs dispersion and narrow particle size
distribution is obtained. The best
formulation of conductive silver ink has
been realized and conductive devices have
been successfully fabricated on a flexible
substrate through the inkjet printing
method.
ACKNOWLEDGEMENTS
The research was supported by the
Ministry of Science, Technology and
Innovation (MOSTI) through the 11th
Malaysia Plan development expenditure
(DE) funding under P.300143 project. The
authors also thank MIMOS Berhad for
financial support and facilities.
REFERENCES
[1] C. Mau Dang, K. Kim Huynh, and D.
My Thi Dang, “Synthesis of Silver
Nanoparticles Using Poly(acrylic
acid) as a Capping Agent for
Conductive Ink in Inkjet Printing
Application,” Sci. Stay. True Here"
Biol. Chem. Res., vol. 6, p. 111, 2019.
[2] L. Ward, T. D. District, H. Chi, and
M. City, “Study of the formation of
silver nanoparticles and silver
nanoplates by chemical reduction
method Dung My `Thi Dang * and
Chien Mau Dang Eric Fribourg-
Blanc,” vol. 12, pp. 456–465, 2015.
[3] H. Lee, K. Chou, and K. Huang,
“Inkjet printing of nanosized silver
colloids,” vol. 2436, 2005.
[4] X. F. Zhang, Z. G. Liu, W. Shen, and
S. Gurunathan, “Silver nanoparticles:
Synthesis, characterization,
properties, applications, and
therapeutic approaches,” Int. J. Mol.
Sci., vol. 17, no. 9, 2016.
[5] G. Suriati, M. Mariatti, and A.
Azizan, “Synthesis of silver
nanoparticles by chemical reduction
method: effect of reducing agent and
surfactant concentration,” Int. J.
Automot. Mech. Eng., vol. ISSN, pp.
1920–1927, 2014.
[6] L. Cao et al., “The preparation of Ag
nanoparticle and ink used for inkjet
printing of paper based conductive
patterns,” Materials (Basel)., vol. 10,
no. 9, Aug. 2017.
[7] A. Lee et al., “Optimization of
experimental parameters to supress
nozzle clogging in inkjet printing,”
Ind. Eng. Chem. Res., vol. 51, no. 40,
Aug. 2012.
[8] M. Chien Dang, T. M. Dung Dang,
and E. Fribourg-Blanc, “Silver
nanoparticles ink synthesis for
conductive patterns fabrication using
inkjet printing technology,” Adv. Nat.
Sci. Nanosci. Nanotechnol., vol. 6, no.
1, 2015.
[9] Y. Li, Y. Wu, and B. S. Ong, “Facile
synthesis of silver nanoparticles
useful for fabrication of high-
conductivity elements for printed
electronics,” J. Am. Chem. Soc., vol.
127, no. 10, pp. 3266–3267, 2005.ao
130