development of indium-free transparent conductive films by the
TRANSCRIPT
INFINITY Consortium:
Development of Indium-Free Transparent Conductive Films by the Sol-Gel Method
M. Skof1,2 , H. Wang2, A. Walker1, A. Rana1, A. Rexach1
1TWI Ltd., UK, 2Materials & Engineering Research Institute, Sheffield Hallam University, UK
T h i s p r o j e c t h a s r e c e i v e d f u n d i n g f r o m t h e E u r o p e a n U n i o n ’ s H o r i z o n 2 0 2 0 r e s e a r c h a n d i n n o v a t i o n p r o g r a m m e u n d e r g r a n t a g r e e m e n t N o 6 4 1 9 2 7 . I n f o r m a t i o n i s p r o v i d e d
a s i s a n d n o g u a r a n t e e o r w a r r a n t y i s g i v e n t h a t t h e i n f o r m a t i o n i s f i t f o r a n y p a r t i c u l a r p u r p o s e . T h e u s e r t h e r e o f u s e s t h e i n f o r m a t i o n a t i t s s o l e r i s k a n d l i a b i l i t y .
© 2 0 1 6 I N F I N I T Y . A l l r i g h t s r e s e r v e d .
Captions
Captions
MotivationThe Project
o Problem: increasing demand for indium tin oxide (ITO),
decreasing resources, high price [1, 2]
o Aim: finding an alternative to ITO as standard for
transparent conductive coatings (TCCs) , f.e. for displays
and solar cells
o Approach: low cost sol-gel process, using widely available
metallic elements and recent advantages in nanostructured
coatings
o Potential ITO Substitute: Titanium dioxide based
material, doped
o Desired outcome: process route to fabricate a printable
ink and low temperature sintering process for conductive
coatings on glass and plastic substrates
Conclusion and Future WorkSummary
o Interference colours suggest that coating was formed
o XRD patterns showed formation of desired TiO2 anatase
structure for sintering temperatures above 600°C
o SEM micrographs indicate porous coating with embedded
nanoparticles
Next Steps
o Vary reaction conditions
• pH, solvent, precursor, water
o Define degree of cross linking in solution and coating
o Optimise drying/curing step (temperature, atmosphere)
o Determine conductivity of coatings
o Change doping levels
Sol-Gel ProcessThe Chemistry
AcknowledgmentsThank you to…
o European Commission, EASME, Horizon 2020
o Alec Gunner, Alan Taylor TWI Ltd.
o Anthony Bell, Sheffield Hallam University
o Simon Rushworth, EpiValence
Contact: [email protected] more information visit: www.infinity-h2020.eu
ResultsCoated Glass Slides
o Coated glass slides show interference colours
o Colours correlate with concentration of precursor (further studies needed)
XRD-Analysis
o Sintering at temperatures below 600°C yields amorphous
structure (left), above 600°C TiO2-anatase peak forms
Microstructure
o Multi-coating process leads to surface defects
o Coating is very porous, connectivity needs to be improved
o Nanoparticles are clearly visible (Figure 9 on right side)
Figure 1: Three main reactions in sol-gel process [3]
(X, Y, Z) = M(OR)x(OH)y(OM)z
X + Y + Z = 4
Figure 2: Hydrolysis/condensation steps in matrix form [3]
o Structure of products depends on reaction rates
• Influenced by nature and concentration of
metal, catalyst, solvent as well as temperature
and pH value of solutions
o Aim: Formation of a crosslinked polymeric networkFigure 3: Network
(schematic)
References
[1] C. Jariwala et.al, Preparation and Characterization of Antimony DopedTin Oxide Thin Films Synthesized by Co-Evaporation of Sn and Sb usingPlasma Assisted Thermal Evaporation, Journal of Nano- and ElectronicPhysics, vol. 5, no. 2, pp. 1-5, 2015.
[2] Y. Furubayashi et.al, Novel transparent conducting oxide: AnataseTi1−xNbxO2, Thin Solid Films, vol. 496, no. 1, pp. 157-159, 2006.
[3] C. Brinker, G. Scherer, Sol-Gel Science. Boston: Academic Press, 1990.
Figure 10: Hydrolysed (left) vs. clear sample
Figure 4: Coated glass slides, precursor concentrations T47: low - T50: high
Figure 5: XRD of T50 samples sintered at 400°C and 500°C
for 25 min, measurement over 1 hour, 20-70 degrees 2theta.
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XRD – Controlling of Sintering
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600°C
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Figure 6: XRD of T50 samples sintered at 600°C and 700°C
for 25 min, measurement over 1 hour, 20-70 degrees 2theta
Figure 7-9: Micrographs showing overview of multi-coated slide on the left, microstructure of surface in the middle and
close-up with nanoparticles visible on the right
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T47 blankT50T49T48