Showing Spotlights 25 - 32 of 43 in category All (newest first):
Impurities during the production process of liquid crystal devices result in mobile ions that influence the LCs' field-induced switching phenomena, resulting in a phenomenon called image sticking, or ghosting. Researchers now have developed a method to reduce the presence of excess ions by doping LCDs with ferroelectric nanoparticles. They demonstrate that this reduction of free ions has coherent impacts on the LC's conductivity, rotational viscosity, and electric field-induced nematic switching.
Oct 16th, 2014
Ferroelectric liquid crystal (FLC) display technology holds the promise of fast switching times, a large viewing angle, and high resolution. FLCs have a spontaneous polarization whose direction is perpendicular to the layer. This spontaneous polarization plays an imperative role in the electro-optic switching of FLCs. Researchers have now developed a technique to amplify the spontaneous polarization by doping graphene into FLCs.
Sep 18th, 2014
The light-emitting electrochemical cell (LEC) shares several external attributes with the OLED, notably the opportunity for soft areal emission from thin-film devices, but its unique electrochemical operation eliminates the principal requirement on inert-atmosphere/vacuum processing as it can comprise solely air-stabile materials. This important intrinsic advantage has inspired recent work on an ambient-air fabrication of LEC devices using scalable means. Introducing a new, purpose-designed spray-sintering deposition technique, researchers have now shown that it is possible to spray out liquid inks onto essentially any surface for the achievement of light emission.
Jun 2nd, 2014
Their unique combinations of liquid and solid-like properties allow liquid crystals to be used pervasively in the electro-optical display technology - known as liquid crystal display (LCD). In new work, researchers have observed that a dilute suspension of a small amount of multi-walled carbon nanotubes in a nematic liquid crystal (in the nematic LC phase the molecules are oriented in parallel but not arranged in well-defined planes) results in a significantly faster nematic switching effect on application of an electric field.
Dec 13th, 2013
Quantum dots are expected to deliver lower cost, higher energy efficiency and greater wavelength control for a wide range of products, including lamps, displays and photovoltaics. Unfortunately, the toxicity of the elements used for efficient quantum dot based LEDs is a severe drawback for many applications. Therefore, light-emitting devices which are based on the non-toxic element silicon are extraordinary promising candidates for future QD-lighting applications. Researchers have now demonstrated highly efficient and widely color-tunable silicon light-emitting diodes (SiLEDs). The emission wavelength of the devices can easily be tuned from the deep red (680 nm) down to the orange/yellow (625 nm) spectral region by simply changing the size of the used size-separated silicon nanocrystals.
Feb 8th, 2013
The size of pixels is one of the key limiting features in the state of the art of holographic displays systems. Holography is a technique that enables a light field to be recorded and later reconstructed when the original light field is no longer present, due to the absence of the original objects. The resolution and field of view in these holographic systems are dictated by the size of the pixel, i.e. the smallest light scattering element. To address the limitations of current holographic systems due to their pixel size, a research team set out to use nanostructures as the smallest possible light-scattering elements for producing holograms. They harnessed the extraordinary conductive and light scattering abilities of nanotubes and patterned an array of carbon nanotubes to produce a high resolution hologram.
Oct 1st, 2012
Quantum dots, because they are both photoluminescent and electroluminescent and have unique physical properties, will be at the core of next-generation displays. Compared to organic luminescent materials used in organic light emitting diodes (OLEDs), QD-based materials have purer colors, longer lifetime, lower manufacturing cost, and lower power consumption. Another key advantage is that, because QDs can be deposited on virtually any substrate, you can expect printable and flexible displays of all sizes. To date, the integration of QDs into a full-color LED structure has not been possible due to the difficulty in patterning individual red-green-blue (RGB) QDs onto the pixelated display panel. Now, a Samsung team has demonstrated a novel transfer printing approach which enables fine patterning of high-quality QD films for large-area (4-inch diagonal), full-color displays mounted on glass as well as on flexible plastic substrates.
Feb 28th, 2011
OLEDs - organic light-emitting diodes - are full of promise for a range of practical applications. OLED technology is based on the phenomenon that certain organic materials emit light when fed by an electric current and it is already used in small electronic device displays in mobile phones, MP3 players, digital cameras, and also some TV screens. With more efficient and cheaper OLED technologies it will possible to make ultra flat, very bright and power-saving OLED televisions, windows that could be used as light source at night, and large-scale organic solar cells. In contrast to regular LEDs, the emissive electroluminescent layer of an OLED consists of a thin-film of organic compounds. Exciton quenching and photon loss processes still limit OLED efficiency and brightness. Organic light-emitting transistors (OLETs) are alternative, planar light sources combining, in the same architecture, the switching mechanism of a thin-film transistor and an electroluminescent device. Thus, OLETs could open a new era in organic optoelectronics and serve as test beds to address general fundamental optoelectronic and photonic issues.
May 6th, 2010