Polymer device

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. 

In Section 13.2, we introduce the materials used in OLEDs. The most obvious classification of the organic materials used in OLEDs is small molecule versus polymer. This distinction relates more to the processing methods used than to the basic principles of operation of the final device. Small molecule materials are typically coated by thermal evaporation in vacuum, whereas polymers are usually spin-coated from solution. Vacuum evaporation lends itself to easy coaling of successive layers. With solution processing, one must consider the compatibility of each layer with the solvents used for coating subsequent layers. Increasingly, multilayered polymer devices arc being described in the literature and, naturally, hybrid devices with layers of both polymer and small molecule have been made. 

The chapter is organized as follows the second section will discuss the photophysics of conjugated polymer/fullerene composites as a standard model for a charge-generating layer in plastic solar cells. Pristine polymer devices will be discussed in the third section while bilayer and interpenetrating network devices are presented in Sections 4 and 5. Section 6 contains some remarks on large area plastic solar cells and Section 7 conclusions. 

Figure 15-10. Schematic band diagrams for single-layer conjugated polymer devices at various values of forward bias. Forward bias is defined with respect lo ITO.

Comparison of the spectral response and of the power efficiency of these first conjugated polymer/fullerene bilayer devices with single layer pure conjugated polymer devices showed that the large potential of the photoinduced charge transfer of a donor-acceptor system was not fully exploited in the bilayers. The devices still suffer from antibatic behavior as well as from a low power conversion efficiency. However, the diode behavior, i.e. the rectification of these devices, was excellent. 

Morii, K. et al. 2000. Characterization of light-emitting polymer devices prepared by ink-jet printing. Proc. 10th Int. Workshop on Inorganic and Organic Electroluminescence. pp. 357-360. 

Novel Devices and Novel Functions in Thin-Film Polymer Devices. 18... 

Section 1.2 gives a brief review of conjugated polymers in semiconducting and metallic phases. Section 1.3 discusses device architectures and their corresponding processes. Section 1.4 introduces some novel devices and their functions in thin-film polymer devices. Section 1.5 is devoted to technical merits of SMOLEDs and PLEDs used as emitter elements in flat-panel displays. 

NOVEL DEVICES AND NOVEL FUNCTIONS IN THIN-FILM POLYMER DEVICES... 

Dual-Function Polymer Device and Display Matrices... 

G Yu, C Zhang, and AJ Heeger, Dual-function semiconducting polymer devices light-emitting and photodetecting diodes, Appl. Phys. Lett., 64 1540-1542, 1994. 

Host Polymer Device Parameter of 2% Ir Complex-Doping Cone. 

Aramid fibers, 13 372-373, 395 asbestos substitute, 3 314t chemical resistance of, 19 731t consumption of, 19 735t mechanical properties of, 13 376 properties of, 1.9 729-7301 as reinforcement materials, 26 756, 760 Aramid films/papers, properties of, 1.9 7331 Aramid polymer device, 16 1 Aramid products, economic aspects of,... 

As the materials mature, it is expected that practical fabrication problems will be solved, and that eventually various grades of E-0 polymers will be available, like photoresist is today, for a variety of different applications and needs. For this reason, polymers represent a unique, potentially powerful addition to the library of materials comprising optoelectronic components, and polymer devices provide new and novel approaches to optical interconnection, electronic packaging, and integrated optics. 

Fig. 1. Graft polymer devices manufactured and sold by Mimotopes Pty Ltd for solid-phase synthesis.

Mimotopes has been involved in the development, use, and commercialization of radiation-grafted polymer surfaces for multiple parallel synthesis since the late 1980s.10-12 Although other workers have reported the use of radiation-graft polymers in solid-phase synthesis,13,14 as far as we are aware, the graft polymer devices manufactured and sold by Mimotopes (SynPhase Crowns, SynPhase Lanterns) are the only current commercial products of this type. These products are presented in Fig. 1. The SynPhase Lanterns are the current design for small molecule synthesis. The initial... 

Chan, J.H., Timperman, A.T., Qin, D., Aebersold, R., Microfabricated polymer devices for automated sample delivery of peptides for analysis by electrospray ionization tandem mass spectrometry. Anal. Chem. 1999, 71, 4437 1444. 

As with crystalline organic semiconductors, there are only few systematic and quantitative studies of bias stress in polymeric TFTs. For example, it is still unclear whether in all polymers a positive VG leads to positive Vj shifts [7, 18]. Here we will concentrate on negative AVT after application of a negative Vg, which is nearly universally observed in p-type devices with a number of semiconductor-dielectric combinations. In the next section of this chapter we will focus on studies of poly-fluorene and polythiophene TFTs, because these are the polymer devices for which bias stress has been most thoroughly characterized in recent years. 

Fig. 12. SHG figure of merit r reported in poled-polymer devices using quasi-phase matching (QPM) and modal dispersion phase matching (MDPM)...

Figure 28 shows the voltage-current characteristics measured for MEH-PPV and the blend polymers. The forward current increases with increasing forward bias voltage for all devices. The turn-on voltages of the blend polymer devices increase as the content of DSiPV increases in the blends. 

The light intensities of the blend polymers are much stronger than that of MEH-PPV homopolymer. The relative quantum efficiencies of MEH-PPV and the blend polymer devices are listed in Table 6. 

The potential benefits of using ionic liquids as electrolytes in conducting polymer devices have been investigated by a number of authors in recent years, for applications such as actuators [8-17], supercapacitors [18-20], electrochromic devices [12, 21] and solar cells [22], with significant improvements in lifetimes and device performance reported. 

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