High-Performance Large-Scale Flexible Optoelectronics Using Ultrathin Silver Films with Tunable Properties

Abstract

One key obstacle in fabricating efficient flexible and printable optoelectronic devices is the absence of ideal flexible transparent conductors with superior optical, electrical, and mechanical properties. Here, highperformance flexible transparent conductors are demonstrated using ultrathin (<10 nm) doped silver films, which exhibit an averaged visible transmittance of 80% without any antireflection coating, sheet resistance less than 20 Ω sq −1 , and mechanical stability over 1000 bending cycles. The conductor is prepared by doping silver with an additive metal (e.g., nickel, copper, titanium, chromium), and its various properties can be readily tuned by either using different doping metal species or controlling the dopant concentration. Centimeter-size, flexible polymer light-emitting diodes are fabricated using a nickel-doped silver-based electrode, and the devices exhibit 30% enhanced current efficiencies compared to their indium tin oxide counterparts, invariant emission spectra at large viewing angles, and operational stability for over 1200 bending circles. In addition, 6 in. flexible low-emissivity coatings are demonstrated using a copper-doped silver-based conductor, which transmit 85.2% of the visible light while rejecting over 90% of the infrared radiation beyond 1250 nm.

Thin‐Metal‐Film‐Based Transparent Conductors: Material Preparation, Optical Design, and Device Applications

“…Consequently, Al atoms are easier to be immobilized on the SiO 2 surface, which contributes to an increased density of heterogeneous nucleation sites for Ag atoms and leads to the early stage formation of an ultrathin and smooth doped Ag film. In addition, similar growth characteristics have been observed in the initial growth stage of Ni‐doped Ag films by Zhang et al [ 140 ] As the film continues to grow, the small metal particles coalesce into larger ones. Compared to a pure Ag film, the particle size of an Al‐doped Ag film only increases slightly when the film thickness increases from 3 to 15 nm (Figure 11a,b).…”

“…Doping an additive metal into the candidate metal through a codeposition process is an efficient approach for preparing high‐quality, ultrathin, and ultrasmooth metal films without any wetting layer. [ 46,137–141 ] As schematically illustrated in Figure a, a small amount of additive metal (denoted as X here, which can be Al, Cu, Ti, Ni, Cr, etc.) is codeposited with Ag, creating a X‐doped Ag film.…”

Plasma Enhanced Atomic Layer Deposition of Plasmonic TiN Ultrathin Films Using TDMATi and NH3

“…Therefore, we have demonstrated a low-temperature PE-ALD deposition and post-deposition treatment of ultrathin plasmonic TiN that is substrate insensitive. Ultrathin plasmonic materials are advantageous for their use as transparent and flexible electrodes in optoelectronic devices, and key to the development of bendable and wearable systems [19,20], and ultrathin films with thicknesses approaching a few monolayers result in strong confinement that can result in quantum effects, such as nonlinearity [21]. Our work opens up potentials of investigating a CMOS compatible ultrathin plasmonic material for these applications.…”

“…Importantly, we introduced a hydrogen-plasma post-deposition treatment to further alter the optical properties of TiN while maintaining the thermal budget at the low temperature of 250 • C. We found that such plasma treatments greatly improved the metallic quality of the films, increasing the ε 1 slope by 1.3 times, from −0.015 to −0.021, on MgO and two times, from −0.012 to −0.024, on Si (100) for 11 nm thick films. Our work demonstrates the feasibility of developing metallic and plasmonic ultrathin TiN films with a PE-ALD deposition and post-deposition treatment that is substrate insensitive and with a low temperature of 250 • C. Our work opens up potentials of investigating a CMOS compatible ultrathin plasmonic material, which have been of interest for flexible transparent optoelectronic devices [19,20] and nonlinear optical applications [21,22].…”

Effect of Annealing on the Microstructure and SERS Performance of Mo-48.2% Ag Films

“…SERS substrates are usually made of noble metal (Ag, Au, Cu) nanomaterials, which can excite local surface plasmon resonance (LSPR) to generate strong extinction and scattering spectra [7]. In particular, SERS substrates composed of Ag nanostructures exhibit better SERS performance [8].…”