Electroluminescence fabricated devices

A metal-insulator-semiconductor-t5q)e electroluminescent (EL) device has been fabricated from PS layers synthesized by photoetching in an HF/I2 solution (Adachi and Kubota 2008). 

Ramrakhiani [155] has reported the EL in nanocrystals and nanocomposites. Semiconductor nanocrystals exhibit many unique properties, which are promising for the improvement of electroluminescence (EL) devices. Combination of polymer and semiconductor nanocrystals allows the fabrication of flexible and lightweight EL devices. The incorporation of nanocrystals in polymer is expected to increase the life of the device and enhance the brightness of emission. The II-VI semiconductor nanoparticles and the nanocomposites in polymers have been synthesized by chemical route. The samples have been characterized and their electroluminescence has been investigated. 

The apphcation of a high electric field across a thin conjugated polymer film has shown the materials to be electroluminescent (216—218). Until recentiy the development of electroluminescent displays has been confined to the use of inorganic semiconductors and a limited number of small molecule dyes as the emitter materials. Expansion to the broad array of conjugated polymers available gives advantages in control of emission frequency (color) and facihty in device fabrication as a result of the ease of processibiUty of soluble polymers (see Chromogenic materials,electrochromic). 

Research on semiconductor nanoparticle technology by chemists, materials scientists, and physicists has already led to the fabrication of a number of devices. Initially, Alivisatos and co-workers developed an electroluminescence device from a dispersion of CdSe nanoparticles capped with a conducting polymer349 and then improved on this by replacing the polymer with a layer of CdS, producing a device with efficiency and lifetime increased by factors of 8 and 10, respectively. 0 Chemical synthetic methods for the assembly of nanocrystal composites, consisting of II-VI quantum dot polymer composite materials,351 represent one important step towards the fabrication of new functional devices that incorporate quantum dots. 

S. Tokito, H. Tanaka, A. Okada, and Y. Taga, High-temperature operation of an electroluminescent device fabricated using a novel triphenylamine derivative, Appl. Phys. Lett., 69 878-880 (1996). 

J. Kido and Y. Iizumi, Fabrication of highly efficient organic electroluminescent devices, Appl. Phys. Lett., 73 2721-2723 (1998). 

MS Weaver and DDC Bradley, Organic electroluminescence devices fabricated with chemical vapour deposited films, Synth. Met., 83 61-66, 1996. 

Organic electroluminescent devices with high operational stability Organic electroluminescent devices with high thermal stability Method of fabricating a TFT-EL pixel Red-emitting organic electroluminescent device... 

The majority of application-related work exploiting the visible PL from PS is aimed at the fabrication of electroluminescent solid-state devices. Only a few other applications of the PL of PS, e.g. the use of luminescent PS for fluorescent labels in biosensing [Akl] or for chemical sensing [Le26], have been proposed. This section therefore focuses on PS-based EL devices. Note that EL from porous structures using wet contacts is discussed in Section 7.4. 

LEDs are electroluminescent devices fabricated from a semiconductor pnjunction and offer inexpensive generation of steady-state or pulsed excitation of low intensity from the near-UV to the near-IR. LEDs epitomize many of the advantages of semiconductor optoelectronics for optical spectroscopy. 

Organic polymers are manufactured and used on a massive scale as plastics and elastomers, films and fibres in areas as diverse as clothing, car tyres, compact discs, packaging materials, prostheses and most recently electroluminescent and electronic devices and sensors. The enormous growth in the use of organic polymeric materials since the 1930s can be mainly attributed to their ease of preparation, lightweight nature and unique ease of fabrication. 

Polymers based on 1,10-phenanthroline and chlorotricarbonylrhenium(I) were fabricated into single-layer light emitting devices. The turn-on voltage was 7 V with a 125 cd/m2 output. The electroluminescence maximum was broad and occurred at 700 nm [111]. 

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