Enhancement Devices

Savio D, Harrasser PC, Basso G. Softgel capsule technology as an enhancer device for the absorption of natural principles in humans. Arzneim Forsch/ Drug Res 1998 48 1104-1106. 

Cyano-substituted PPVs have low electrical conductivity due to the electron withdrawing ability of cyano group, however, they have become important materials for the fabrication of LEDs. While LED devices constructed from unsub-stituted-PPV exhibit efficiencies of less than 1%, similar LED devices fabricated with cyano-substituted PPVs have displayed efficiencies of over 4%. To further enhance device performance, proccessible polymers containing cyano functionalities were synthesized utilizing monomers possessing solubilizing alkoxy chains for ease of device construction. 

Future advances in precursor purity and manufacturing technology, real-time monitoring of chemical reactions, MOCVD reactor chamber design, computer-controlled epitaxial growth systems, detailed chemical process models, and real-time process control will lead to improved process efficiencies, reduced hazardous waste, and enhanced device reproducibility, yield, and performance. The future of MOCVD is certainly bright. We are on the frontier of a great expansion of the abilities of MOCVD to provide materials for products that improve and expand the human experience on earth, under the oceans, and in space. 

Biosensors and devices may also include fiber components. Biosensors essentially contain two main components. These are the sensing element, which senses the molecule of interest, and the transducer, which generates a signal. Amyloid fibrils and other protein nanofibers could be used in biosensors in two ways. The first is as a scaffold to immobilize the sensing element on a nanoscale as described above. The second use is as a coating on the transducer where the presence of the protein fiber could enhance device performance. This enhancement could be carried out either with or without the aid of a further conductive coating (see Section 4.1 above). 

Displaced enhancement devices Electro-static fields... 

First, the reduction of a carrier injection barrier between organic/electrode interfaces was reported to enhance device duration.55,61 Although joule heat at the interfaces is supposed to induce microcrystallization of organic molecules and successive destruction of balanced hole and electron injection and transport, the precise degradation mechanism is still unclear. 

As mentioned in Sect. 2.2.1.3 [33], we proposed that a trace amount of /3-phase, induced by the use of an electron-deficient moiety (TAZ) as an end-capper for PFO, can improve device performance to give a better blue purity. Following the idea of /3-phase formation, we further proposed a novel simple physical method to generate /3-phase at a content of up to 1.32% in a PFO film spin-coated on a substrate (the remaining part is amorphous phase) by immersing it in a mixed solvent/non-solvent (tetrahydrofuran/methanol) for a few seconds [45]. The device based on PFO with 1.32% / -phase (ITO/PEDOT PSS/emitting polymer/CsF/Al) has a dramatically enhanced device efficiency and an improved blue-color purity of 3.85 cd A-1 (external quantum efficiency, 3.33%) and CIE of x+y = 0.283 (less than the limit of... 

In addition to the incorporation of fluorescent chromophores in PF, phosphorescent moieties have been widely used to copolymerize with fluorene or as pendent group in PFs for color tuning (via the selection of ligands chelated to heavy metals) and performance improvement. The ability to enhance device performance via phosphors is because strong spin-orbit coupling (resulting from the inclusion of heavy metal atoms in the phosphor structure) can efficiently utilize triplet excitons for electroluminescence and theoretically there are three times as many as triplet as singlet excitons. 

Introduction of CFx thin film on top of the ITO anode as HTL via plasma polymerization of CHF3 can also enhance device performance of PFO-based PLED, as reported by us [79]. At the optimal C/F atom ratio using the radio frequency power 35 W (see Table 2) as determined by X-ray photoelectron spectrometer, the device performance based on the ITO/CFx(35 W)/PFO/CsF/Ca/Al configuration is optimal having maximum current efficiency of 3.1 cdA 1 and maximum brightness of8400 cdm 2 much better than 1.3 cd A-1 and 1800 cd m-2 for the device with PEDOT PSS as HTL. The improved device performance was attributed to a better balance between hole and electron fluxes because the CFx (35 W) layer possesses an Ip value of 5.6 eV (see Table 2), as determined by ultraviolet photoelectron spectroscopy data, and therefore causes a lower hole-injection barrier to the PFO layer (0.2 eV) than that of 0.7 eV for PEDOT PSS. 

The diversification of energy sources tailored to the requirements and resources of each country using nature s renewable resources such as the sun (photovoltaics), wind power, geothermal energy and biomass is a definite requirement. If solar cells are chosen to provide an alternative to fossil fuels, significant research work is needed (i) to develop new routes for the production of crystalline silicon, (ii) in the development of amorphous silicon hybrid materials that could result in enhanced efficiencies, (iii) for further development of thin-layer technology, (iv) in concerted efforts for cheaper and more stable dyes, (v) in improving the efficiency of the dye-sensitized cells and (vi) in process development to deliver enhanced device performances, ensure sustainability and reduce production costs on an industrial scale. 

Possibly one of the most difficult tasks each year is that of writing the General Review of Proton Magnetic Resonance because of the enormous number of papers dealing with such a wide variety of topics. However, I hope the more specialized chapters dealing with specific topics of proton NMR will help to broaden these aspects. The advent of sensitivity enhancement devices has clearly spurred the spectro-scopist to make greater use of carbon-13 satellite spectra. The numerous references, to these satellite spectra, contained in this Volume will undoubtedly encourage chemists to make use of the information contained therein. 

Displaced enhancement devices are inserted into the flow channel so as to indirectly improve energy transport at the heated surface. They are used with forced flow. 

A rather large variety of tube inserts falls into the category of displaced enhancement devices. The heated surface is left essentially intact, and the fluid flow near the surface is altered by the insert, which might be metallic mesh, static mixer elements, rings, disks, or balls. Laminar heat transfer data for uniform-wall-temperature tubes and uniformly heated tubes are plotted in Figs. 11.26 and 11.27, respectively. The isothermal friction factors are plotted in Fig. 11.28. 

Mesh or spiral brush inserts were used by Megerlin et al. [182] to enhance turbulent heat transfer in short channels subjected to high heat flux. The largest recorded improvements in turbulent heat transfer coefficients were obtained—up to 8.5 times however, the pressure drop was up to 2800 times larger. In general, it appears that these displaced enhancement devices are useful in very few practical turbulent situations, for reasons of pressure drop, plugging or fouling, and structural considerations. 

Roy, S.D. Manoukian, E. Transdermal delivery of ketorolac tromethamine Permeation enhancement, device design, and pharmacokinetics in healthy humans. J.Pharm.Sci., 1995, 84, 1190-1196... 

Improved semiconductor devices and circuits tend to be achieved primarily through advances in either device density, performance or functionality. At times, all three elements are realized simultaneously. The improvements can be accomplished in several ways. One approach is to design new circuit families, which very often create enhanced device functionalities and performances. In contrast to this, device density gains typically demand a much greater investment of process efforts in the form of a relentless pursuit of better tolerance control of all the various process and tool parameters. It may, however, also be coupled with the introduction of new process methods and/or tools with enhanced process capabilities. 

Significant amount of research has been dedicated to two material systems MDMO-PPV PCBM (MDMO-PPV poly(2-methoxy-5-(3, 7 -dimethyl-octyloxy)-l,4-phenylenevinylene)) and RR-P3HT PCBM, which represent the state-of-the-art polymer solar cell technology. Because there are excellent review papers on the MDMO-PPV PCBM system in the literature, in this section we will only focus on the recent improvements in RR-P3HT PCBM system, especially the approaches to optimize the active blend layer for enhancing device efficiency. 

Birnstock, J., Canzler, T., Hofmann, M. et al. 2008. PIN OLEDs-improved structures and materials to enhance device lifetime. J. Soc. Inf. Display 16 221. 

---