Chaobin Yang

An all‐solution‐processed transparent conductive electrode with sheet resistance one order of magnitude smaller than conventional nanowire‐based transparent conductors has been developed. This is achieved by integrating all‐solution produced microwires with a nanowire solution and electroplating and electrowelding. Advantages of the resulting transparent conductor are indium‐free, vacuum‐free, and lithographic‐facility‐free, and metallic‐mask‐free, with small domain size (≈10 μm²), low sheet resistance (R_s < 1 Ω □⁻¹), high optical transmittance (T > 80%), mechanical flexibility, and scalability, thus making it an excellent replacement for ITO.

A scalable and a fully solution‐based method is developed to produce environmentally stable Ag micro/nanowire networks for transparent conductors. By applying a self‐cracking, water‐soluble acrylate copolymer film as a photoresist mask, the need for formal photomask fabrication and costly vacuum and lithographic facilities is obviated. Also, an increase in adhesion and a decrease in roughness of the metal networks is demonstrated by depositing metal into the regions created by the glass etch step. As a result, the networks can potentially be inexpensively scaled to large areas, as well as be flexible after removal from the substrate. They also exhibit record values of figures of merit that have been employed in the literature, offering a possibly excellent replacement for ITO.

Metallic network, an important indium tin oxide (ITO) replacement, is extensively studied due to its advantages in optoelectronic properties and mechanical flexibility. Vacuum sputtering/evaporation‐free processing is an essential step for roll‐to‐roll production of low‐cost and large‐size metallic network transparent electrodes. In this paper, a high performance metallic crack‐nanonetwork (CNN) is demonstrated by employing a sputtering/evaporation‐free process, which combines advantages of the standard CNN processing with electroless plating, enabled by unique properties of the commercial amorphous fluoropolymer CYTOP. This network shows outstanding optoelectronic performance, with the best figure of merit ≈ 20000 (at T ≈ 86.4% and R_s ≈ 0.13 Ω sq⁻¹), as well as excellent mechanical flexibility and stability. This network outperforms the current industry standard, ITO, in performance and cost, as a result of the elimination of the sputtering/evaporation step. This is therefore a dramatic step toward replacing ITO with a metallic cracking nanonetwork.

Present on-chip optical communication technology uses near-infrared light, but visible wavelengths would allow system miniaturization and higher energy confinement. Towards this end, we report a nanoscale wireless communication system that operates at visible wavelengths via in-plane information transmission. Here, plasmonic antenna radiation mediates a three-step conversion process (surface plasmon → photon → surface plasmon) with in-plane efficiency (plasmon → plasmon) of 38% for antenna separation 4λ₀ (with λ₀ the free-space excitation wavelength). Information transmission is demonstrated at bandwidths in the Hz and MHz ranges. This work opens the possibility of optical conveyance of information using plasmonic antennas for on-chip communication technology.

A solar cell based on a hot electron plasmon protection effect is proposed and made plausible by simulations, non-local modeling of the response, and quantum mechanical calculations. In this cell, a thin-film, plasmonic metamaterial structure acts as both an efficient photon absorber in the visible frequency range and a plasmonic resonator in the IR range, the latter of which absorbs and protects against phonon emission the free energy of the hot electrons in an adjacent semiconductor junction. We show that in this structure, electron–plasmon scattering is much more efficient than electron–phonon scattering in cooling-off hot electrons, and the plasmon-stored energy is recoverable as an additional cell voltage. The proposed structure could become a prototype of a new generation of high efficiency solar cells.