Devices light emitting diode

Conjugated organic polymers have been studied extensively over the last twenty years, in part, because of the fundamental and technological interest in their optic and electronic properties. Applications that have been demonstrated for these materials include their use as batteries, sensors, electrochromic devices, light-emitting diodes, and field effect transistors.(i-9) A unique advantage of conjugated polymer materials for these applications is that the properties of the polymer can be... 

Electrochromic devices, where a transparent window can be turned opaque at selected regions of the electromagnetic spectrum under a potential, are another area in which PA copolymers and substituted PAs may have potential applications. Promising research opportunities also exist in the fabrication of PA-based controlled-release devices, non-linear optical devices, light-emitting diodes, and radar shielding. The readers are encouraged to consult some older [191-196] and more recent [197-199] review articles on these subjects. 

Industrial Applications Solar ceUs photoelectric device light emitting diodes color filters liquid-crystal displays thin films inks lithographic plate photographic materials recording materials sol-gel materials photonics adhesive paints thermoplastics colored bubbles textiles, entertainment products toys ... 

Industrial Applications Dye laser electrochromic display device light-emitting diode semiconductors thin film materials laundry detergent paper textiles ... 

Interest in AIN, GaN, InN and their alloys for device applications as blue light-emitting diodes and blue lasers has recently opened up new areas of high-pressure synthesis. Near atmospheric pressure, GaN and InN are nnstable with respect to decomposition to the elements far below the temperatures where they might melt. Thus, large boules of these materials typically used to make semiconductor devices caimot be grown from the... 

LEDs as piGHT GENERATION - LIGHT-EMITTING DIODES] (Vol 15) Optoelectronic imaging devices... 

Semiconductors are materials that are characterized by resistivities iatermediate between those of metals and of iasulators. The study of organic semiconductors has grown from research on conductivity mechanisms and stmcture—property relationships ia soHds to iaclude appHcations-based research on working semiconductor junction devices. Organic materials are now used ia transistors, photochromic devices, and commercially viable light-emitting diodes, and the utility of organic semiconductors continues to iacrease. 

Fig. 7. Schematic of light emitting diodes (a) single-layer device (b) single heteiostmctuie (c) double heteiostmctuie.

Light-emitting diodes are the most commercially important compound semiconductor devices in terms of both doUar and volume sales. The 1991 worldwide compound semiconductor device market totaled 2.8 biUion (39). Light-emitting diodes accounted for ca 1.9 biUion of this market. Visible and ir LEDs represented 37 and 30%, respectively. These markets are expected to grow as LEDs are increasingly employed in advanced appHcations. 

By 1988, a number of devices such as a MOSFET transistor had been developed by the use of poly(acetylene) (Burroughes et al. 1988), but further advances in the following decade led to field-effect transistors and, most notably, to the exploitation of electroluminescence in polymer devices, mentioned in Friend s 1994 survey but much more fully described in a later, particularly clear paper (Friend et al. 1999). The polymeric light-emitting diodes (LEDs) described here consist in essence of a polymer film between two electrodes, one of them transparent, with careful control of the interfaces between polymer and electrodes (which are coated with appropriate films). PPV is the polymer of choice. 

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