THE recent fabrication of light-emitting diodes (LEDs) from conjugated polymers1,2demonstrates the technological potential of this class of electronic materials. A variety of colours are possible, because the wavelength of luminescence emission can be chemically tuned during synthesis1–4. In addition, the mechanical properties of polymers suggest that light-emitting structures can be made that are more flexible than their inorganic counterparts, provided appropriate materials can be found for the substrate and electrodes. Here we report the fabrication of a fully flexible LED using poly(ethylene terephthalate) as the substrate, soluble poly-aniline as the hole-injecting electrode, a substituted poly(1,4-phenylene-vinylene) as the electroluminescent layer and calcium as the electron-injecting top contract. The structure is mechanically robust and may be sharply bent without failure. The LED is easily visible under room lighting and has an external quantum efficiency of about 1%. With a turn-on voltage for light emission of 2–3 V, the 'plastic' LED demonstrates that this unique combination of optical, electrical and mechanical properties can be used to make novel structures that are compatible with conventional devices.

Flexible light-emitting diodes made from soluble conducting polymers

Progress in preparation, processing and applications of polyaniline

Counter-ion induced processibility of conducting polyaniline and of conducting polyblends of polyaniline in bulk polymers

Polyaniline: A historical survey

Polymers are lightweight, flexible, solution-processable materials that are promising for low-cost printed electronics as well as for mass-produced and large-area applications. Previous studies dem ...

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Semi-metallic polymers

We present optical-absorption data together with band-structure calculations for the polaron lattice and bipolaron lattice for the highly conducting form of polyaniline, proton-doped polyemeraldine. We show that the polaron-lattice band structure fully accounts for the observed optical transitions. These results are in marked contrast with the electronic structure of other doped conducting polymers, in that only one single broad polaron band appears deep in the gap together with a very narrow band nearly degenerate with the conduction-band edge.

Polaron lattice in highly conducting polyaniline: Theoretical and optical studies.

Insulator-to-metal transition in polyaniline

http://www.phys.ufl.edu/%7Etanner/PDFS/Epstein87sm-polyanaline.pdf

Insulator-to-metal transition in polyaniline: Effect of protonation in emeraldine

The optical properties of segmented trans-(CH${)}_{\mathit{x}}$ and trans-(CD${)}_{\mathit{x}}$ are presented. It is shown from the resonance-Raman-scattering data that a clustering of ${\mathit{sp}}^{3}$ defects occurs upon the introduction of deuterium atoms in trans-(CH${)}_{\mathit{x}}$ and hydrogen atoms in trans-(CD${)}_{\mathit{x}}$. In view of this effect, the segmented polyacetylene sample still contains long conjugated segments whose electronic properties can account for the almost unchanged optical-band-gap values. The doping-induced infrared bands in different segmented samples are interpreted by considering the perturbation of the dopant on the lattice dynamics of long segments. Also, the dc-conductivity results are discussed in terms of the presence of clusters of ${\mathit{sp}}^{3}$ defects, which can limit both interchain and intrachain transport processes.

Optical spectroscopic investigation of segmented trans-polyacetylene.

http://www.phys.ufl.edu/~tanner/PDFS/Woo91sm-CHx.pdf

H. S. Woo

Papers

Polaron lattice in highly conducting polyaniline: Theoretical and optical studies.

Insulator-to-metal transition in polyaniline

Insulator-to-metal transition in polyaniline: Effect of protonation in emeraldine

Optical spectroscopic investigation of segmented trans-polyacetylene.

Polarized Absorption in Oriented 'New' (CH)x