Mechanical integrity of hybrid indium-free electrodes forflexibledevices
article
Maintaining electrical conductivity, optical transparency, and mechanical integrity against bending andstretching are key requirements forflexible transparent electrodes. Transparent conducting oxides(TCOs) are widely used thinfilm electrodes in optoelectronic devices. However, these materials arebrittle and reducingfilm thickness to improve their mechanical integrity compromises their electricalperformance. Here we combine TCO thinfilms with metal grids embedded in a polymer substrate tocreate hybrid electrodes with low sheet resistance and high resilience to bending. Amorphous zinc tinoxide (ZTO) and aluminum-doped zinc oxide (AZO)films sputtered onto polyethylene-terephthalate(PET) substrates with and without embedded metal grids are studied. The hybrid electrodes have anoptical absorptance below 5% in the visible range and their electrical sheet resistance is less than 1U/sq.The critical strain for tensile failure is analyzed through a combination of electrical measurements andin-situobservations of crack initiation and propagation during tensile loading. The mean critical strain forfailure of the AZO/metal grid is 8.5% and that of the ZTO/metal grid is as high as 10%. The AZO and ZTOfilms alone present critical strain values around 0.6% and 1% respectively, demonstrating that theaddition of the metal grid considerably improves the resistance onset strain of the electrodes far beyondthese critical strain limits.
TNO Identifier
865846
ISSN
15661199
Source
Organic Electronics, 35, pp. 136-141.
Publisher
Elsevier
Place of publication
Amsterdam
Pages
136-141
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