Poly(3,4‐ethylenedioxythiophene) Derived from Poly(ionic liquid) for the Use as Hole‐Injecting Material in Organic Light‐Emitting Diodes

Abstract

We report that poly(3,4-ethylenedioxythiophene) derived from poly(ionic liquid) (PEDOT:PIL) constitutes a unique polymeric hole-injecting material capable of improving device lifetime in organic light-emitting diodes (OLEDs). Imidazolium-based poly(ionic liquid)s were engineered to impart non-acidic and non-aqueous properties to PEDOT without compromising any other properties of PEDOT. A fluorescent OLED was fabricated using PEDOT:PIL as a hole-injection layer and subjected to a performance evaluation test. In comparison with a control device using a conventional PEDOT-based material, the device with PEDOT:PIL was found to achieve a significant improvement in terms of device lifetime. This improvement was attributed to a lower indium content in the PEDOT:PIL layer, which can be also interpreted as the effective protection characteristics of PEDOT:PIL for indium extraction from the electrodes.

Polyaniline‐Based Conducting Polymer Compositions with a High Work Function for Hole‐Injection Layers in Organic Light‐Emitting Diodes: Formation of Ohmic Contacts

“…Although conducting polymers such as poly(ethylene dioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS, WF = 5.0-5.2 eV) and polyaniline doped with PSS (PANI:PSS, WF = 5.2-5.3 eV) are alternatives to smallmolecule HILs in SM-OLEDs, only a few reports have described solution-processed HILs in SM-OLEDs because of the remaining high injection barrier and low efficiency. [3,4] Recently, high-performance, solution-processable HILs have attracted much attention in OLED research for the development of highly effi-cient and stable SM-OLED panels fabricated by a solution process. [5] Current research requires new strategies for developing solution processable and efficient hole-injection buffer layers for high-performance SM-OLEDs.…”

Nanocomposites Based on Luminescent Colloidal Nanocrystals and Polymeric Ionic Liquids towards Optoelectronic Applications

“…N -vinyl-3-butylimidazolium (VBuImBr) bromide was prepared by quaternization following a procedure already described [46–49]. The monomer was recovered as a white solid with 100% yield and investigated by NMR spectroscopy, whose data perfectly matched those reported in the literature.…”

Adhesion and degradation of organic and hybrid organic-inorganic light-emitting devices

“…The bubbles observed on the other hand could be caused by the diffusion of gases through layer imperfections (in form of scratches and pinholes) due to the hygroscopic nature of the PEDOT:PSS used as a HTL. [46][47][48] It is also important to note here that the pressures from the bubbles observed in Figures 10 and 11 were not visible in devices not subjected initially to bias for $60 min. This suggests that the bias is associated with the nucleation of bubble or black spot formation at the sub-micron scale that cannot be resolved by optical microscopy.…”