Bo-Ru Yang

Microchannel Wetting for Controllable Patterning and Alignment of Silver Nanowire with High Resolution.

Patterning and alignment of conductive nanowires are essential for good electrical isolation and high conductivity in various applications. Herein a facile bottom-up, additive technique is developed to pattern and align silver nanowires (AgNWs) by manipulating wetting of dispersions in microchannels. By forming hydrophobic/hydrophilic micropatterns down to 8 μm with fluoropolymer (Cytop) and SiO2, the aqueous AgNW dispersions with the optimized surface tension and viscosity self-assemble into microdroplets and then dry to form anisotropic AgNW networks. The alignment degree characterized by the full width at half-maximum (FWHM) can be well-controlled from 39.8° to 84.1° by changing the width of microchannels. A mechanism is proposed and validated by statistical analysis on AgNW alignment, and a static model is proposed to guide the patterning of general NWs. The alignment reduced well the electrical resistivity of AgNW networks by a factor of 5 because of the formation of efficient percolation path for carrier conduction.

Emiflective Display with Integration of Reflective Liquid Crystal Display and Organic Light Emitting Diode

A novel emi-flective display which integrates a reflective liquid crystal display (R-LCD) and an organic light emitting diode (OLED) was demonstrated, whose OLED achieved a gain factor of 8 in contrast ratio (CR) compared with the conventional OLED. Under the high light ambience, the R-LCD is sustained with the CR of 10:1 at the viewing angle between ±55°; while in the dim ambience, the OLED is operated with the CR of 5000:1 at ±50°. By replacing the backlight system with OLED, emi-flective display has the benefits of lighter weight (<90%), thinner form factor (<40%), and lower power consumption (<2%, under sunlight) compared with the conventional LCD; therefore, to be very applicable for mobile products.

Fabrication of Embedded Silver Nanowires on Arbitrary Substrates with Enhanced Stability via Chemisorbed Alkanethiolate

We propose a versatile yet practical transferring technique to fabricate a high performance and extremely stable silver nanowire (AgNW) transparent electrode on arbitrary substrates. Hydroxylated poly(ethylene glycol) terephthalate (PET) or poly(dimethylsiloxane) (PDMS) deposited with AgNWs was selectively decorated to lower its polar surface energy, so that the AgNWs were easily and efficiently transferred into an epoxy resin (EPR) as a freestanding film (AgNWs-EPR) or onto various substrates. The AgNWs-EPR capped with alkanethiolate monolayers exhibits high conductivity, low roughness, ultraflexibility, and strong corrosion resistance. Using the transferring process, AgNWs-EPR was successfully constructed on rough, adhesive, flimsy, or complex curved substrates, including PET, thin optically clear adhesive, papers, a beaker, convex spherical PDMS, and leaves. A flexible touch panel enabling multitouch and a curved transparent heater on a beaker were first fabricated by using the composite film. These demonstrations suggest that the proposed technique for AgNWs is a promising strategy toward the next generation of flexible/portable/wearable electronics.

Nitrogen-Doped Amorphous InZnSnO Thin Film Transistors With a Tandem Structure for High-Mobility and Reliable Operations

The threshold voltage shift (AVth) in amorphous InZnSnO thin-film transistors (a-IZTO TFTs) during negative gate-bias stress (NGBS) is significantly improved by nitrogen doping. Numerous N-In bonds eliminate donorlike subgap states near the Fermi level, which improve stability during stress but degrade electron mobility. We developed tandem TFTs with an a-IZTO:N layer on top of an a-IZTO layer, in which mobility reaches 31.76 ± 0.81 cm2/Vs and the reliability is improved. Especially, AVth in NGBS is reduced by 80% for pristine a-IZTO devices. This simple but an effective method achieves fast and reliable operation in the a-IZTO TFTs.

High-brightness relaxed-bend state in a pi cell stabilized by synchronized polymerization

The authors report a synchronized polymer-stabilization technique which can be used to stabilize the nonpermanent states in liquid crystal devices. In this paper, a relaxed-bend state in a pi cell which has a lifetime of only 80ms is observed and then stabilized by this proposed technique. After stabilizing, the pi cell is immune to undesirable recovery into the splay or twist states, and its optical contrast is much higher than that of the conventional polymer-stabilized pi cell.

Emi-Flective Display Device with Attribute of High Glare-Free-Ambient-Contrast-Ratio

We have demonstrated the integration of an organic light emitting device (OLED) and a reflective liquid crystal display (R-LCD) which was termed an emi-flective display. The glare-free-ambient-contrast-ratio (GFA-CR) was used to evaluate the image quality of display devices under ambient light. Through integrating the OLED with R-LCD, the GFA-CR of the device achieved an improvement by a factor of 8 compared with that of the OLED alone. Moreover, the integrated R-LCD showed a GFA-CR of 100:1 within a viewing cone of 20° which can suppress the wash-out of OLED and is more power-saving in the sunlight. Therefore, an emi-flective display is a promising technique for mobile applications.

Volumetric Scattering Layer for Flexible Transflective Display

A flexible transflective liquid crystal display (FTF-LCD) which combined a flexible LCD and a flexible organic light emitting diode was demonstrated. Under high light ambience (reflected luminance of 250 nits), a LCD incorporated with a volumetric scattering layer (VSL) showed a contrast ratio of 10:1 at the viewing cone of 60° in the reflection mode. By adding the VSL to the LCD, the haze component was increased by a factor of 3.3. With the advantages of small form factor, flexibility, power-saving, and legibility in bright ambience, the FTF-LCD is very applicable to mobile products.

Investigation of the transient symmetric H state in a pi cell

The so-called symmetric H (Hs) state has been reported to have submillisecond response times, which results from the symmetric profile of the liquid crystal director; however, no direct evidence has been obtained to show the profile symmetry. The difficulty in proving this symmetric structure by direct observation results from the short lifetime of Hs state (typically around a few tens of milliseconds). In the work reported here, the authors utilize a burst driving method along with stroboscopic illumination from blue and red light emitting diodes to capture conoscopic images for the Hs director profile; these showed good agreement with their modeling.

P‐121: Electrokinetics of Charged‐Particles in Microcup Electrophoretic Displays

To fully understand the physical mechanism in electrophoretic displays, both current and optical responses are discussed to investigate the charging behavior, including the transient current, intermediate-state current, discharge current, and the observed bump characteristics, along with their applications.

Physical activation of innate immunity by spiky particles

Microbial biochemicals have been indicated as the primary stimulators of innate immunity, the first line of the body’s defence against infections. However, the influence of topological features on a microbe’s surface on immune responses remains largely unknown. Here we demonstrate the ability of TiO2 microparticles decorated with nanospikes (spiky particles) to activate and amplify the immune response in vitro and in vivo. The nanospikes exert mechanical stress on the cells, which results in potassium efflux and inflammasome activation in macrophages and dendritic cells during phagocytosis. The spiky particles augment antigen-specific humoral and cellular immune responses in the presence of monophosphoryl lipid A and elicit protective immunity against tumour growth and influenza viral infection. The study offers insights into how surface physical cues can tune the activation of innate immunity and provides a basis for engineering particles with increased immunogenicity and adjuvanticity.Spikes on the surface of TiO2 microparticles, mimicking the nanotopological structures found on pathogens, boost the immune response in animal models and can be used to enhance the immunogenic effect of vaccines and adjuvants.