Novel Light Emitting Diode Using Organic Electroluminescence Microcapsules

Abstract

Novel light emitting diodes (LEDs) were prepared using electroluminescence (EL) material/polymer microcapsules (ELC). N‐vinylcarbazole as a hole‐transporting component and methyl methacrylate (MMA) were copolymerized for producing the seed particles using dispersion polymerization. An oxadiazole derivative, synthesized as a electron‐transporting component, and tris(8‐hydroxyquinolinato) aluminium(III) (Alq3) were incorporated into the polymer particles by using the solute co‐diffusion method (SCM). The LEDs for the EL characterization were fabricated in a thin sandwich configuration: Al anode/ELC/ITO cathode. The surface imaging of the LED prepared using ELC was performed by atomic force microscopy (AFM). The EL characteristics of the ELC were investigated by UV, photoelectron and luminescence spectroscopy, and the current‐voltage and the light‐voltage characteristics for the LED were determined.

Monodisperse polymer particles synthesized by seeded polymerization techniques

“…Here we introduce a couple of applications. We have expanded this SCM to fabricate light emitting diodes (LED) by using electroluminescence material/polymer microcapsules [44,45]. In this approach, we first produce poly(methyl methacrylate) (PMMA) seed particles by copolymerizing a hole-transporting component with methyl methacrylate.…”

Novel Light‐Emitting Diodes Using Organic Electroluminescent Nanocapsules

“…Synthesis of 2-(3¢-Nitrophenyl)-5-(4¢-methoxyphenyl)-1,3,4-oxadiazole (NPD) [17]: p-Methoxybenzoic hydrazide, p-nitrobenzoyl chloride, and methansulfonic acid were refluxed in toluene until the reaction was complete. Progress was monitored by thin layer chromatography (TLC, petroleum ether/EtOAc, 1:1).…”

“…[12,14±16] In particular, EL from polymeric nanocapsules has been reported. [12] In our previous study, [17] a small-molecular EL material was introduced into polymer microcapsules by the solute co-diffusion method (SCM). From the current± voltage±luminescence (I±V±L) characteristics of the LED prepared from the microcapsules, it was confirmed that threedimensional polymeric microcapsules were suitable for an application in EL devices.…”

“…[16] The unfolding process results in a large solvent exposure of hydrophobic residues that were shielded in the core of the protein in its native state. [17] We call our protein device a field-effect transistor since we exploit a field effect to modulate the resistance of the protein monolayer and change the I±V characteristics of the device. [18] The field in the actual device is at least one order of magnitude larger and we cannot investigate directly these fields in fluorescence experiments (since it would be necessary to apply hundreds of volts).…”

Freestanding microscale 3D polymeric structures with biologically-derived shapes and nanoscale features

“…Significant global effort is underway to develop shapetailored polymeric microstructures with fine (down to nanoscale) features for medical, cosmetic, aerospace, environmental, agricultural, optical, fluidic, and microelectromechanical applications. [1][2][3][4][5][6][7][8][9][10] Microfabrication routes based on layer-by-layer two-dimensional (2D) techniques, such as lithographic micromachining methods developed for the silicon microelectronics industry, are not particularly well suited for fabricating threedimensional (3D) polymeric structures with complex shapes (e.g., curved 3D surfaces) and with very fine (down to nanoscale) features. 11,12 However, alternative approaches capable of direct 3D micro/nanofabrication must also be scalable to allow for high-throughput production.…”