Luminescence Electroluminescence

The electroluminescence spectra of the single-layer devices are depicted in Figure 16-40. For all these OPV5s, EL spectra coincided with the solid-state photoluminescence spectra, indicating that the same excited states are involved in both PL and EL. The broad luminescence spectrum for Ooct-OPV5-CN" is attributed to excimer emission (Section 16.3.1.4). 

The composition of the copolymer determines its electroluminescence efficiency. Optimal efficiency (0.3%) was achieved in system 34 when the feed ratio of monomer 4 to monomer 34 was 9 1. This represents a 30-fold improvement in luminescence efficiency relative to PPV in the same device configuration (AlALOj/polymer/Al) 58, 62. Copolymer 33 has found uses as waveguides and... 

In electroluminescence devices (LEDs) ionized traps form space charges, which govern the charge carrier injection from metal electrodes into the active material [21]. The same states that trap charge carriers may also act as a recombination center for the non-radiative decay of excitons. Therefore, the luminescence efficiency as well as charge earner transport in LEDs are influenced by traps. Both factors determine the quantum efficiency of LEDs. 

U. Lemmer. R. F. Malm, Y. Wada, A. Greiner, H. Basslcv. E.O. Gobel, Time resolved luminescence study of recombination processes in electroluminescent polymers, Appl. Phys. Lett. 1993, 62, 2827. 

Having investigated the electrochemical behavior of ZnSe, and in view of the well-known blue luminescence of the compound, the previous authors extended their work to study electroluminescence from I-doped n-ZnSe crystals under anodic polarization in aqueous media containing metal ions such as Cu(II) and Sn(II) [123]. 

Strickert HH, Tong JR, EUis AB (1982) Luminescent photoelectrochemical cells. 6. Spatial aspects of the photoluminescence and electroluminescence of cadmium selenide electrodes. J Am Chem Soc 104 581-588... 

It is worth noting some historical aspects in relation to the instrumentation for observing phosphorescence. Harvey describes in his book that pinhole and the prism setup from Newton were used by Zanotti (1748) and Dessaignes (1811) to study inorganic phosphors, and by Priestley (1767) for the observation of electroluminescence [3], None of them were capable of obtaining a spectrum utilizing Newton s apparatus that is, improved instrumentation was required for further spectroscopic developments. Of practical use for the observation of luminescence were the spectroscopes from Willaston (1802) and Frauenhofer (1814) [13]. 

The term chemiluminescence was not introduced until 1888, when Wiedemann defined the term luminescence. He was able to classify luminescence phenomena of six different kinds, according to the manner of excitation photoluminescence, caused by the absorption of light, electroluminescence, produced in... 

Polarized luminescence from oriented molecular materials 1999 Ladder-type materials 1999 Electroluminescence in organics... 

Spiro-FPAl/TPBI/Bphen Cs/Al. A very low operating voltage of 3.4 V at luminance of 1000 cd/m2 was obtained, which is the lowest value reported for either small-molecule or polymer blue electroluminescent devices. Pure blue color with CIE coordinates (0.14, 0.14) have been measured with very high current (4.5 cd/A) and quantum efficiencies (3.0% at 100 cd/m2 at 3.15 V) [245]. In another paper, Spiro-FPA2 (126) was used as a host material with an OLED device structure of ITO/CuPc/NPD/spiro-FPA2 l%TBP/Alq3/LiF that produces a high luminescent efficiency of 4.9 cd/A [246]. 

T. Mori, K. Miyachi, T. Kichimi, and T. Mizutani, Electrical and luminescent properties of color-changeable organic electroluminescent diode using squarylium dyes, Jpn. J. Appl. Phys., 33 6594-6598 (1994). 

L. Huang, H. Tian, F. Li, D. Gao, Y. Huang, and C. Huang, Blue organic electroluminescent devices based on a distyrylarylene derivatives as emitting layer and a terbium complex as electrontransporting layer, J. Luminescence, 97 55-59 (2002). 

F. He, H. Xu, B. Yang, Y. Duan, L. Tian, K. Huang, Y. Ma, S. Liu, S. Feng, and J. Shen, Oligomeric phenylenevinylene with cross dipole arrangement and amorphous morphology enhanced solid-state luminescence efficiency and electroluminescence performance, Adv. Mater., 17 2710-2714 (2005). 

Blue luminescent materials for organic electroluminescent devices White light-emitting organic electroluminescent devices Blue organic electroluminescent devices... 

Electroluminescent device with modified thin film luminescent zone... 

Electroluminescent device with organic luminescent medium... 

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