Manganese-Doped Tin Oxide for Highly Flexible and Transparent Multilayer Electrodes with Index-Matching Layers.

We fabricated transparent Mn (2.59 wt.%)-doped tin oxide (MTO)/Ag/MTO films with refractive index-matching layers (IMLs) on a polyethylene terephthalate (PET) substrate. To reduce refractive index-mismatching, polydimethylsiloxane (PDMS) and MTO layers were inserted between the MTO/Ag/MTO multilayer film and the PET substrate. MTO and Ag were deposited by RF/DC magnetron sputtering at room temperature, whereas spin-coating was used to deposit PDMS at various dilution ratios in hexane. In this study, pattern visibility was examined by comparing the differences in the color and reflectance of oxide/metal/oxide multilayers before and after adding the PDMS and MTO IMLs. In addition, the effects of the PDMS dilution ratio on the electrical and optical characteristics were also investigated. The MTO/Ag/MTO/PDMS/MTO multilayer films showed high transmittance (>86% at 550 nm) except at the dilution ratio of 1:50. As the PDMS dilution ratio increased from 1:50 to 1:200, the reflectance difference (Δ) increased from 0.08% to 0.35% and the color difference (Δ*) increased from 0.31 to 1.23. The maximum resistance changes of the multilayer films were 0.126% and 0.124% after outer and inner bending, respectively, for 10,000 cycles with a radius of curvature of 4 mm.