Optimizing ultrathin Ag films for high performance oxide-metal-oxide flexible transparent electrodes through surface energy modulation and template-stripping procedures

Abstract

Among new flexible transparent conductive electrode (TCE) candidates, ultrathin Ag film (UTAF) is attractive for its extremely low resistance and relatively high transparency. However, the performances of UTAF based TCEs critically depend on the threshold thickness for growth of continuous Ag films and the film morphologies. Here, we demonstrate that these two parameters could be strongly altered through the modulation of substrate surface energy. By minimizing the surface energy difference between the Ag film and substrate, a 9 nm UTAF with a sheet resistance down to 6.9 Ω sq−1 can be obtained using an electron-beam evaporation process. The resultant UTAF is completely continuous and exhibits smoother morphologies and smaller optical absorbances in comparison to the counterpart of granular-type Ag film at the same thickness without surface modulation. Template-stripping procedure is further developed to transfer the UTAFs to flexible polymer matrixes and construct Al2O3/Ag/MoOx (AAM) electrodes with excellent surface morphology as well as optical and electronic characteristics, including a root-mean-square roughness below 0.21 nm, a transparency up to 93.85% at 550 nm and a sheet resistance as low as 7.39 Ω sq−1. These AAM based electrodes also show superiority in mechanical robustness, thermal oxidation stability and shape memory property.

Supersmooth Ta2O5/Ag/Polyetherimide Film as the Rear Transparent Electrode for High Performance Semitransparent Perovskite Solar Cells

“…The line‐profiles of surface morphology obtained from AFM images show the typical peak‐to‐valley feature in outline across the surface, which confirms again that the films are composed of separate silver islands, which results in the large sheet resistances of 9 nm thick silver films on both PCBM and ZrAcac shown in Figure a, as well as the corresponding transmission spectra shown in Figure c. This isolate island growth characteristic comes from the high surface energy of substrate for the nucleation and thus the following growth of silver . The smaller grain size and roughness of the ultrathin silver film on ZrAcac means lower interaction energy between silver and ZrAcac, along with the contribution of flatter film surface.…”

Fully Solution‐Processed Semi‐Transparent Perovskite Solar Cells With Ink‐Jet Printed Silver Nanowires Top Electrode

“…As seen here, the thermal evaporated thin Ag electrode with a layer thickness of 7.2 nm showed a low AVT of 47.5%. Surprisingly, this 7.2 nm Ag electrode is not conductive at all, which is speculated to be due to the island formation mechanism . Figure S1b, in Supporting Information shows the photographic images of the printed AgNW electrode, clearly shows the transparency of the different Ag electrodes.…”

Quantum-dot light-emitting diode with ultrathin Au electrode embedded in solution-processed phosphomolybdic acid

“…19,20 Transmittance of ultrathin metal is considerably improved aer embedding thin metal lm in dielectric layers of vacuum-deposited high refractive index oxides which are responsible for reectance reduction due to light coupling with surface plasmon polaritons (SPP) at a metal/ oxide interface. 21 These oxide/metal/oxide multilayers have been already investigated in various combinations including metal oxides: MoO 3 , 22,23 WO 3 , 24,25 ZnO, 26 ZnS, 27 as well as different metals: gold, 28 silver, 29 or copper. 30 Although silver is the most promising metal due to its champion conductivity and low cost, it has a lower work function in contrast to gold which is tailored better to most of organic hole transport layers (HTLs).…”