The discovery of organic electroluminescence (EL) in manufacturable small molecule [1] and p-conjugated polymer [2] thin-film format has led to the commercialization of organic light-emitting diode (OLED) technology and the development of many other novel semiconductor devices. One of the key goals for research in this field is high-performance, fully plastic electronic devices, but before such technology can be realized, organic electrode materials with conductivities and stabilities comparable to standard inorganic materials must be developed. Indium tin oxide (ITO) is the present industry standard transparent inorganic anode material for rigid devices, such as optical displays and solar cells. Attempts have also been made at implementing ITO in an emerging generation of flexible devices, but it is not an ideal choice owing to its inherent brittleness and susceptibility to conductivity changes after bending. [3][4][5] When this is considered alongside the ever-increasing cost of indium, it is clear that there is a pressing need to develop organic-based electrode materials for both flexible and rigid substrate devices. Here, we report the synthesis and optoelectronic properties of highly conductive (≤ 1180 S cm -1 ) poly(3,4-ethylenedioxythiophene) (PEDOT) films prepared by vapor phase polymerization (VPP). We focus on their application in ITO-free OLEDs as a patternable organic anode material. We describe devices fabricated on glass and flexible plastic substrates with efficiencies (16.8 and 9.8 lm W PEDOT is an especially promising organic electrode material. Though insoluble in all common solvents, PEDOT films exhibit a number of desirable properties in the oxidized state, including high conductivity, good stability, and high thin-film transparency. [6,7] It is possible to circumvent the low solubility of PEDOT using a water-soluble polyelectrolyte such as poly(styrene sulfonic acid) (PSSA) during polymerization in water, yielding a PEDOT-PSS aqueous composite with good film-forming properties. [8,9] However, the conductivity of a PEDOT-PSS film is typically no more than ca. 10 S cm -1 , well below the level typical of ITO (ca. 4000 S cm -1 ). Researchers have explored several methods for raising the conductivity, including the addition of a range of secondary dopants.

Fabrication of polymer multilayer structures has previously been difficult to achieve due to the need for solvent orthogonality to ensure that sequential deposition does not damage any underlying layers. In this paper we report an alternative approach based on a stamp transfer printing process. We demonstrate its suitability for uniform and patterned multilayer deposition (c.f. figure) and use it as a means to engineer enhanced performance photodiode structures.

We report improved performance from ITO‐free organic light emitting diodes (OLEDs) prepared with vapour phase polymerization poly(3,4‐ethylenedioxythiophene) (VPP‐PEDOT) anodes. By inserting additional interfacial anode layers based on triarylamine polymers, we demonstrate VPP‐PEDOT OLEDs on rigid glass substrates that display improved electroluminescence characteristics, and which have efficiencies that are comparable to equivalent ITO‐based devices. We also report on the development of flexible OLEDs (FOLEDs) with VPP‐PEDOT anodes, demonstrating efficient red, green, blue and white‐emitting devices with significantly improved device rectification.

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We use a combinatorial approach to develop molecular plastic solar cells based on soluble fullerene derivatives blended with conjugated polymers. A combinatorial way of sample preparation is well suited to deal with the multitude of possible combinations of the components of such blends. We use high mobility poly(thiophene) and poly( phenylenevinylene) derivatives to be combined with acceptors. Gradients of methanofullerene/polymer concentration were formed by diusion of the low molecular weight component in the spin-cast polymer matrix. Likewise the gradients of zinc phthalocyanine/C 60 were prepared by co-evaporation of the two materials from two sources to make a linear array of photodiode devices. Photo-and electrophysical properties, such as absorption, luminescence, short circuit photocurrent and open circuit photovoltage, were measured using a specially designed installation with a resolution of 70±100 m. Clear evidence was obtained that the photoconversion ef®ciency increased with the amount of methanofullerene up to very high levels, in the case of methanofullerene/polymer blends, verifying the important role of the acceptor in the photoconversion. By choosing the optimal ratio between C 60 and ZnPc in the evaporated layer it is possible to obtain high photocurrent in the 600±700 nm range, due to the added contribution from photoinduced electron transfer between the two molecules.