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The fabrication of a high performance organic light-emitting diode used a series of functionalized polymers with triphenyldiamine derivative side-groups as the thermally deposited hole transport.

A model based on Poisson's equation and conservation law of charges is derived to determine the characteristics of organic light emitting-diodes (OELDs). The model is used to determine current-voltage characteristics, relative quantum efficiency and emission distribution of OLEDs. Results show that at least one barrier height should be low for low voltage device operation. High brightness devices also require high mobility.

Solution electrochemical studies were conducted on lumophores, dopants and hole-transport agents of aluminum-quinolate-based organic light-emitting diodes (OLEDS) along with the characterization of their electrogenerated chemiluminescence. Results showed that cross reactions between the cation radical state of the hole-transport agent and the anion radical state of the lumophore in Alq3/4,4'-bis(m-tolyphenylamino)biphenyl (TPD) OLEDS can serve as a pathway to the production of the Alq3 emissive state. The cation radical state of TPD was more stable than the same state for Alq3.

Research was conducted to develop a two-layer, blue organic light-emitting diode with improved color purity and enhanced efficiency. It was found that the insertion of a 4,4'-bis(2,2-diphenylvinyl)-1,1'-biphenyl emission layer and a LiF/Al cathode improves efficiency by 50-fold and increases color purity up to 476 nm. The deposition of sub-monolayer amounts of LiF results to a significant decline in the effective work-function of the aluminum.

This paper presents simple fabrication of optical waveguides using a novel photosensitive polyimide (PSPI). PSPI has a glass transition temperature (Tg) of 330°C and is directly patterned by ultraviolet (UV) exposure and wet-chemical development, lending itself to low-cost fabrication techniques. The fabricated waveguides possess low optical absorption at 1.3 and 1.5 μm. Single and multimode buried ridge waveguides were made and tested, and a 0.4-dB/cm optical propagation loss is measured at 1.55 μm. [ABSTRACT FROM PUBLISHER]

Focuses on the design of considerations for active matrix organic light emitting diode (OLED) arrays. Applications of OLED; Charge feedthrough and injection effects; Parasitic extraction and R-C modelling of pixels;

Lower cost and high-throughput printing techniques, such as screen printing, have a great promise in the fabrication of organic light-emitting devices. We investigate the effects of solution viscosity and screen mesh count on the printed layer thickness and device performance. The results also demonstrate, for the first time to our knowledge, the use of screenprinting to deposit ultrathin layers of less than 15 nm with rms surface roughness of less than 1.5 nm [ABSTRACT FROM PUBLISHER]

A report is presented on free falling droplet energy harvesting using piezoelectric cantilevers. The harvester incorporates a multimorph clamped-free cantilever which is composed of five layers of lead zirconate titanate piezoelectric thick films. During the impact, the droplet kinetic energy is transferred into the form of mechanical stress forcing the piezoelectric structure to vibrate. Experimental results show energy of 0.3 µJ per droplet. The scenario of moderate falling drop intensity, i.e. 230 drops per second, yields a total energy of 400 µJ. [ABSTRACT FROM AUTHOR]

Presents a highly efficient organic light emitting diode with an aluminum cathode. Determination of the maximum luminance; Insertion of an optimum thickness of lithium fluoride as a buffer layer; Use of the tunneling theory in explaining the enhanced efficiency.

Examines the characteristics and quantum efficiency of single layer organic light emitting diodes (LED). Use of a model based on Fowler-Nordheim injection and classical electrostatics to define LED; Relationship between electrode barrier height and carrier mobility; Effect of high mobility materials on lasers.

Evaluates the use of quantum confined nanocrystals of lead sulphide in glass as intracavity saturable absorbers to obtain passive continuous wave mode locking in a chromium:forsterite laser. Maintenance of mode locking; Variation of the quantum dots; Advantage of inexpensive solid state saturable absorbers.

Highlights: [•] ZnO Nanowall network with honeycomb structure grown by PLD. [•] No metal catalyst and no chemical etching. [•] ZnO Nanowall can be grown on different types of substrates. [•] Low oxygen pressure and high quality 2D nanostructures were grown. [•] They exhibit a non-uniform size high quality honeycomb structure with low deep level defects. [Copyright &y& Elsevier]

We investigate the dependence of the performance of non-doped blue light emitting devices with thermally activated delayed fluorescence (TADF) material bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (DMAC-DPS) emission layer on hole and electron transport layers as well as emission layer thickness and study the underlying device physics. On this basis, efficient green and orange devices using DMAC-DPS as host material and TADF material (4s,6s)-2,4,5,6-tetra(9H-carbazol-9-yl)isophthalonitrile (4CzIPN) or 2,3,5,6-tetrakis(3,6-diphenylcarbazol-9-yl)-1,4-dicyanobenzene (4CzTPN-Ph) as emitting dopant are reported. In addition, white devices using single DMAC-DPS: 4CzTPN-Ph emission layer show the maximum external quantum efficiency of 13.4%, maximum power efficiency of 38.3 lm W −1 and current-insensitive Commission Internationale de I'Eclairage (CIE) coordinates of (0.29, 0.39). Compared to the approach of combining TADF host and fluorescent dopant, the present devices enable the utilization of all excitons for light emission and the adoption of broad dopant concentration without significantly affecting device efficiency, which is important for the realization of the desired colour purity for display applications, while maintaining the advantages of simple-structure and low-cost. [ABSTRACT FROM AUTHOR]