Electroluminescence and fluorescence emission of poly(n-vinylcarbazole) and poly(n-vinylcarbazole)-Ir(ppy)3-based organic light-emitting devices prepared with different solvents

Abstract

We present a study of spectroscopic proprieties of poly(n-vinylcarbazole) (PVK) and PVK doped with iridium complexes tris[2-phenylpyridinato-C2,N]iridium(III) (IrðppyÞ 3 ) films prepared by spin-coating from toluene and chlorobenzene solutions. A different molecular organization of the polymer on the substrate during the spin-coating process can be produced using solvents with different boiling temperatures. The modified molecular rearrangement affects the emission properties of the PVK material and the consequent energy transfer to the doping molecules. Both static and dynamic fluorescence emissions properties have been studied, for pure PVK and PVK doped with different weight percentage of IrðppyÞ 3 . Different organic light-emitting devices, using a simple architecture, have been prepared with both solvents to test the change in electroluminescence spectral shape and in electrical characteristic, and the final efficiencies of the devices have been evaluated. Fig. 1 (a) Chemical structures and (b) HOMO LUMO levels of PVK and IrðppyÞ 3 . Bruno et al.: Electroluminescence and fluorescence emission of poly(n-vinylcarbazole). Downloaded From: http://photonicsforenergy.spiedigitallibrary.org/ on 05/16/2015 Terms of Use: http://spiedl.org/terms Bruno et al.: Electroluminescence and fluorescence emission of poly(n-vinylcarbazole). Downloaded From: http://photonicsforenergy.spiedigitallibrary.org/ on 05/16/2015 Terms of Use: http://spiedl.org/terms Bruno et al.: Electroluminescence and fluorescence emission of poly(n-vinylcarbazole). Downloaded From: http://photonicsforenergy.spiedigitallibrary.org/ on 05/16/2015 Terms of Use: http://spiedl.org/terms Bruno et al.: Electroluminescence and fluorescence emission of poly(n-vinylcarbazole). Downloaded From: http://photonicsforenergy.spiedigitallibrary.org/ on 05/16/2015 Terms of Use: http://spiedl.org/terms Bruno et al.: Electroluminescence and fluorescence emission of poly(n-vinylcarbazole). Downloaded From: http://photonicsforenergy.spiedigitallibrary.org/ on 05/16/2015 Terms of Use: http://spiedl.org/terms Bruno et al.: Electroluminescence and fluorescence emission of poly(n-vinylcarbazole). Downloaded From: http://photonicsforenergy.spiedigitallibrary.org/ on 05/16/2015 Terms of Use: http://spiedl.org/terms Bruno et al.: Electroluminescence and fluorescence emission of poly(n-vinylcarbazole).

Modeling and numerical simulation of electrical and optical characteristics of a quantum dot light-emitting diode based on the hopping mobility model: Influence of quantum dot concentration

“…Based on the results of research on the size and ligand effects on the DOS of CdSe nanocrystals, [57][58][59] we deduce that the QDs used in this study have a Gaussianlike peak in the CB with an energy of E CB = 2.2 eV and a Gaussian-like peak in the VB with an energy of E VB = 5.6 eV. On the other hand, the PVK HOMO and LUMO energy levels are measured [60] at E HOMO = 5.5 eV and E LUMO = 2.2 eV. Therefore, the QD's CB peak is aligned with the PVK HOMO peak, and the center of the QD's VB peak is 0.1 eV outside the PVK gap.…”

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“…In relation to the FTO produced at laboratory, it presented the highest sheet resistance value, and this aspect decreases considerably the final performance of OLED devices, as low luminance, with increase of the threshold voltage, or causes a different electrical behavior compared by common I-V curve of diode 50 . Performance presented by FTO produced at laboratory can be related by its amorphous structure, interfering in the locomotion of electrical charges (as observed by low carriers concentration and Hall mobility), once a crystalline structure promotes better injection of electrical charges by fluorine in the FTO, as observed in some semiconductor materials (silicon, as example).…”

Rewritable resistive memory effect in poly[N-(3-(9H-carbazol-9-yl)propyl)-methacrylamide] memristor

“…From these measurements, the energy position of the HOMO level of PCaPMA was determined as E HOMO = −5.23 eV, slightly higher than PVCa, where the value E HOMO = −5.34 eV was obtained, consistent with previous literature reports. 29,45,46…”

“…From these measurements, the energy position of the HOMO level of PCaPMA was determined as E HOMO = À5.23 eV, slightly higher than PVCa, where the value E HOMO = À5.34 eV was obtained, consistent with previous literature reports. 29,45,46 Both polymers displayed CV curves that were not fully reversible and exhibited only weak reduction peaks. The bandgap, E g , was therefore determined from the Tauc plot of the optical absorption spectra.…”