Showing Spotlights 25 - 32 of 46 in category All (newest first):
Polymer Dispersed Liquid Crystals (PDLCs) are micrometer-sized birefringent Liquid Crystal domains dispersed in an optically transparent continuous polymer matrix. The peculiarity of a PDLC system is that of scattering different amounts of an impinging light beam intensity, depending on the strength of an external electric field that is, eventually, applied to the system. A new generation of polymer-dispersed liquid crystals is based on a room temperature, polymerizable, nematic LC host.
Jan 13th, 2015
White-light-emitting diodes have many advantages over forms of lighting - incandescent, fluorescent and halogen - and this solid-state lighting technique is bound to make major inroads into the commercial and household markets. Researchers have now designed precursors and chemical processes to synthesize intercrossed carbon nanomaterials with relatively pure hydroxy surface states for the first time, which enable them to overcome the aggregation-induced quenching (AIQ) effect, and to emit stable yellow-orange luminescence in both colloidal and solid states.
Nov 25th, 2014
Researchers have demonstrated that they can print interwoven structures of quantum dots, polymers, metal nanoparticles, etc, to create the first fully 3D printed LEDs, in which every component is 3D printed. At the fundamental level, 3D printing should be entirely capable of creating spatially heterogeneous multi-material structures by dispensing a wide range of material classes with disparate viscosities and functionalities, including semiconducting colloidal nanomaterials, elastomeric matrices, organic polymers, and liquid and solid metals.
Nov 5th, 2014
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