Electroluminescence intensity current density

The /3-diketonate [Nd(dbm)3bath] (see figs. 41 and 117) has a photoluminescence quantum efficiency of 0.33% in dmso-7r, solution at a 1 mM concentration. It has been introduced as the active 20-nm thick layer into an OLED having an ITO electrode with a sheet resistance of 40 il cm-2, TPD as hole transporting layer with a thickness of 40 nm, and bathocuproine (BCP) (40 nm) as the electron injection and transporting layer (see fig. 117). The electroluminescence spectrum is identical to the photoluminescence emission the luminescence intensity at 1.07 pm versus current density curve deviates from linearity from approximately 10 mA cm-2 on, due to triplet-triplet annihilation. Near-IR electroluminescent efficiency <2el has been determined by comparison with [Eu(dbm)3bath] for which the total photoluminescence quantum yield in dmso-tig at a concentration of 1 mM is Dpi, = 6% upon ligand excitation, while its external electroluminescence efficiency is 0.14% (3.2 cdm-2 at 1 mAcm-2) ... 

Fig. 2.35 Electroluminescence spectra from the same PFB/F8BT bilayer device as in Fig. 2.31 measured at 330 K (a) and 289 K (c) at different voltages. The spectra are not normalized and higher intensity corresponds to higher voltage. The corresponding voltages and current densities are plotted in panels (b) and (c), respectively. The data corresponding to 3.2Vapplied bias are marked with an arrow.

Figure 4. Electroluminescence intensity and current density vs. time for an MI2 doped MEH-PPy)/rrO device at TV in the forward bias mode. Reproduced with permission from Synthetic Metals (in press). Copyright 1998 Elsevier Science Ltd.

The tum-on current shifts to lower electric fields with increasing n - according to the facilitated injection and transport of holes (oxidation demonstrated by the arrows in Fig. 11.9(a)). Figure 11.9(c) shows the relative intensities of the electroluminescence as a function of the current density. The highest value ij = 10 was measured for 2c (n = 3). The relative electroluminescence intensities (Fig. 11.9(c)) at a current density of 1 mA cm show a dependence on n which... 

With the aid of photon localization and enhancement by DUV-LSPR [59-61] LSPR, the output power of LEDs is expected to improve [62-65]. Huang et al. demonstrated for the first time that the enhanced emission of DUV-LEDs coupled to LSPRs generated by Al nanoparticles prepared on quantum wells (QWs) [66, 67]. Size- and density-controlled Al nanoparticles were fabricated by OAD (see Sect. 9.1) on the surface of Al cGai cN (x = 0.25), used as an active layer (see Fig. 9.6). Figure 9.7 shows the emitted electroluminescence (EL) spectra of samples with and without Al nanoparticles and the enhancement ratio that represents their relative intensities under a 15-mA injection current. Figure 9.7a, b shows the top emission (epitaxial layer side) and bottom emission(sapphire substrate side), respectively. A maximum tenfold top-emission enhancement and a maximum 2.8-fold bottom-emission enhancement were... 

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