Organic Electropolymerized Multilayers for Light-Emitting Diodes and Displays

In electrochemistry, the carbazole is generally coupled to dimer but not to polymer. This work has reported that organic electropolymerization (OEP) of 4,4',4″-tri(N-carbazolyl)triphenylamine (TCTA) would form a high cross-linked carbazole polymer by its high activity/reversibility and a synchronous viscosity control. It has significantly improved the OEP film quality of both hole-transporting and electroluminescent layers in organic light-emitting diodes. As a result, the conductivity and power efficiency of the organic light-emitting diodes with TCTA are eight and four times of that without TCTA. A prototype display device with a 1.7 in. monochrome passive matrix of 58 ppi under the driving chip is successfully fabricated with accurate pixel size and uniform electroluminescence, which shows a great potential of OEP in the electroluminescent application.

Improving the Electropolymerization Properties of Fluorene-Bridged Dicarbazole Monomers through Polyfluoroalkyl Side Chains

The facile functionalization of the fluorene scaffold at the 2,7-positions was utilized to provide access to two soluble carbazole-π-carbazole derivatives CFC-H1 and CFC-F1 featuring fully hydrogenated and polyfluorinated alkyl chains at the 9-position of the fluorene π-bridging unit, respectively. The optical and electrochemical properties of the new dicarbazoles were investigated. Their electrochemical polymerization over Pt and indium tin oxide electrodes allowed the generation of electroactive polymeric films, whose physicochemical characteristics were strongly dependent on the kind of alkyl chain present on the fluorene bridge. In particular, the electropolymerization of the polyfluorinated monomer allowed the fabrication of thin films with good electrical conductivity, reversible electrochemical processes, good electrochromic properties, and enhanced water repellency with respect to its nonfluorinated analogue.

TFT-Directed Electroplating of RGB Luminescent Films without a Vacuum or Mask toward a Full-Color AMOLED Pixel Matrix

The thin-film transistor (TFT) driving circuit is a separate electronic component embedded within the panel itself to switch the current for each pixel in active-matrix organic light-emitting diode displays. We reported a TFT-directed dye electroplating method to fabricate pixels; this would be a new method to deposit films on prepatterned electrode for organic full-color display, where TFT driving circuit provide a switching current signal to drive and direct dye depositing on selected RGB pixels. A prototype patterned color pixel matrix was achieved, as high-quality light-emitting films with uniform morphology, pure RGB chromaticity, and stable output.

Polarized Thin Layer Deposited Electrochemically on Aluminum-Doped Zinc Oxide as a Cathode Interlayer for Highly Efficient Organic Electronics

Herein, we demonstrated a polarized thin film (PBzP2C4) electrochemically deposited from phosphonate and a carbazole-difunctionalized conjugated molecule as an aluminum-doped zinc oxide (AZO) modifier for high-performance inverted organic solar cells (OSCs)/polymer light-emitting diodes (PLEDs). The PBzP2C4 film showed a controllable thickness and fully covered the surface of AZO, resulting in a smooth and uniform electrode. PBzP2C4 modification reduced the W_F of AZO and highly improved the electron extraction/injection in inverted OSCs/PLEDs. As a result, a maximum power conversion efficiency of 10.35% was achieved for inverted OSCs with PTB7-Th:PC₇₁BM as the active layer, and a maximum luminous efficiency of 21.4 cd A^-1 was obtained for inverted PLEDs based on P-PPV.

Structure–property relationship in fluorene-based polymer films obtained by electropolymerization of 4,4′-(9-fluorenylidene)-dianiline

For the first time, the electropolymerization of 4,4′-(9-fluorenylidene)-dianiline and physico-chemical properties of the obtained polymer films are reported.