Electroluminescence OLED configuration

Figure 9. The electroluminescence (EL) spectra of OLED in Si02/rr0/(NTCDI-DPM)2/Al configuration at 8 Volts. Peak 1 and 2 correspond to EL of monomers and aggr tes respectively. Inset voltage dependence EL at (A) 3 V and (B) 6 V of Si02/IT0/(NTCDI-HM)4/Al OLED-configuration.

FIGURE 6.24 (a) Luminous efficiency of two top-emitting OLEDs with a configuration of glass/Ag (200 nm)/ITO (130 nm)/PEDOT (80 nm)/Ph-PPV (80 nm)/semi transparent cathode (closed circles), and Al-PET/acrylic layer/Ag (200 nm)/CFx (0.3 nm)/Ph-PPV (110 nm)/semitransparent cathode (open diamonds), (b) A photo image showing a flexible top-emitting electroluminescent device on an Al-PET substrate. 

The configuration and construction of monolayer and multilayer OLEDs have undergone substantial changes and modifications since these first reports of organic electroluminescence from low-molar-mass materials. Several types of OLEDs using small organic and organometallic molecules are described schematically below. 

In 1990, Kido etal. [16] first reported the europium complex tris(thienyltrifluoro-acetonato) europium [Eu(TTA)3], based OLED in which the complex was molecularly dispersed in holetransporting poly(methylphenylsilane) (PMPS). Luminescence started at 12 V, and a maximum intensity of 0.3cdm at 18 V was achieved when the device was operated in continuous DC mode (biased ITO positive) with the configuration ITO/PMPS-Eu(TTA)3/PBD/Mg/Ag [PBD = 2-(4-biphenyl)-5-(4-tert-butylphenyl)-l,3,4-oxadiazole, the structure shown in Eigure 11.4, being used as the electron-transporting layer]. Since then, many Eu(III) complexes and related electroluminescent devices have been studied extensively. 

Fig. 21 Top normalized electroluminescence spectra for (dotted line) 30, (dashed line) [Pt(C1 ANAN)(C CC6H4Me-4)], and (continuous line) 40 at 4% doping level and multilayer configuration of device. Bottom current density, voltage and luminance characteristics (inset luminescent efficiency vs current density) for OLED using 30 as emitter as 4% doping level (Reproduced with permission from [36a]. Copyright 2002 Royal Society of Chemistry)...

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