Light-emitting devices

Interface control of light-emitted devices based on pyridine-containing conjugated polymers 99ACR217. 

In the many reports on photoelectron spectroscopy, studies on the interface formation between PPVs and metals, focus mainly on the two most commonly used top electrode metals in polymer light emitting device structures, namely aluminum [55-62] and calcium [62-67]. Other metals studied include chromium [55, 68], gold [69], nickel [69], sodium [70, 71], and rubidium [72], For the cases of nickel, gold, and chromium deposited on top of the polymer surfaces, interactions with the polymers are reported [55, 68]. In the case of the interface between PPV on top of metallic chromium, however, no interaction with the polymer was detected [55]. The results concerning the interaction between chromium and PPV indicates two different effects, namely the polymer-on-metal versus the metal-on-polymer interface formation. Next, the PPV interface formation with aluminum and calcium will be discussed in more detail. 

The final remark of this section concerns the polaronic transition of m-LPPP around 1.9 eV, where we can observe P2 with its vibronic replica P3 at 2.1 eV. In Figure 9-20 we show this polaronic absorption in m-LPPP as detected by photoin-duced absorption (a), chaige-induced absorption in conventional light-emitting devices (b), and chemical redox-reaction (c). Only under pholoexcilation, which creates both neutral and charged species, the triplet signal at 1.3 eV is also observed. 

The enormous progress in the field of electroluminescent conjugated polymers has led to performances of oiganic light-emitting devices (LEDs) that are comparable and in some aspects superior to their inorganic counterparts 11). Quantum efficiencies in excess of 5% have been demonstrated [2] and show that a high fraction of the injected carriers in a polymeric electroluminescence (EL) device form electronic excitations which recombine radiatively. 

S.V. Frolov, A. Fujii, D. Chinn, Z.V. Vardeny, K. Yoshino, R. V. Gregory, Cylindrical microlasers and light emitting devices from conducting polymers, Appl. Phys. Lett. 1998, 72, 2811. 

Fig. 4.14 SEM micrograph of CVD nickel-coated carbon microfibers (INCOEIBER 12K20) before (a) and after (b) the cathodic electrosynthesis of ZnSe on their surfaces (the scale bar is 8 and 10 p.m, respectively). Such low-dimensional substrates find apphcation in new-generation photovoltaic solar cells, chemical/biological sensors, and light-emitting devices. (Reprinted from [127], Copyright 2009, with permission from Elsevier)...

Wong, K.M.-C., Zhu,X., Hung, L.-L., Zhu, N., Yam, V.W.-W. and Kwok, H.-S. (2005) A novel class of phosphorescent gold(lll) alkynyl-based organic light-emitting devices with tunable colour. Chemical Communications, 2906—2908. 

A selection of applications is presented in the following subsections solar cells, TFTs, light sensors (visible, IR, X-ray), and chemical sensors. Also, light-emitting devices, in particular utilizing erbium incorporation in a-Si H, are presented. Finally, electrostatic loudspeakers in which an a-Si H film is incorporated are described. Details of various applications described here, as well as many other applications, can be found in the excellent edited books [4, 5, 11,13, 574]. 

A.D Amico and G. Fortunato, Ambient Sensors Hiroshi Kukimoto, Amorphous Light-Emitting Devices Robert J. Phelan, Jr., Fast Detectors and Modulators Jacques I. Pankove, Hybrid Structures... 

Hebner, T. Wu, G Marcy, D. Lu, M. Sturm, J. 1998. Ink-jet printing of doped polymers for organic light emitting devices. Appl. Phys. Lett. 72 519-521. 

Kim, C. Forrest, S. R. 2003. Fabrication of organic light-emitting devices by low-pressure cold welding. Adv. Mater. 15 541-545. 

Organic Light-Emitting Devices and Their Applications for Flat-Panel Displays... 

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