This article presents the synthesis and characterization of a series of cross-conjugated D-π-A-π-D-based photoinitiators for the two-photon-induced photopolymerization process. Different donor and acceptor functionalities and derivatives containing double and triple bonds in the conjugated backbone allowed the evaluation of structure-activity relationship. Investigation of the basic photophysical properties showed high extinction coefficients at around 400 nm and none or vanishingly small emission quantum yields. The evaluated initiators showed at least similar activity, and in some cases broader processing windows than well-known highly active initiators from the literature and by far better results than commercially available initiators in terms of two-photon-induced microfabrication. These results are well in accordance with the TPA cross section values for the compounds measured by z-scan analysis. By using optimized parameters, structures with line widths of about 250 nm were obtained at photoinitiator concentrations as low as 0.05 wt %.

Intrigued by the good performance of 1,5‐diphenylpenta‐1,4‐diyn‐3‐one (DPD) as photoinitiator for radical polymerization we prepared and investigated several donor substituted derivatives. UV‐Vis spectroscopy revealed a gradual red‐shift of λmax and higher extinction in the order of the donor capability. A methoxy‐substituted derivative (O‐DPD) exhibited significant photoinitiation activity in photo‐DSC experiments. Steady state photolysis experiments showed decreased decomposition rates with increasing donor capability. A dimethylamino derivative N‐DPD was even photostable under these conditions. Because of to the D‐π‐A‐π‐D system of these compounds two‐photon induced 3D photopolymerization experiments were performed and N‐DPD showed outstanding performance compared to often applied single photon initiators. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3280–3291, 2007

The long-term target of producing all-organic devices requires custom-designed dielectric materials able to be applied and patterned with a wide range of new and fast deposition and patterning methods. Inorganic-organic hybrid polymers such as organic modified ceramics (ORMOCERs) have recently gained considerable attention in polymer electronics. Consisting of organically functionalized inorganic-oxidic units, their material properties can be tuned over a wide range and, in addition, their processing is very flexible providing good compatibility to many materials and substrates and allowing for direct patterning. A study on the application of different ORMOCER systems as gate dielectric layers in organic thin-film transistors (OTFTs) with pentacene as the organic semiconductor and directly structured contact holes is presented. Depending on the chemistry of the underlying ORMOCER system, different morphologies of the thermally evaporated pentacene were observed and correlated to the electrical characteristics of the transistor devices. In some cases, OTFTs with excellent electrical performance were achieved, showing intrinsic field-effect mobility values up to 1 cm(2)/V s. Based on the high charge-carrier mobility of the pentacene-ORMOCER interface and the good dielectric, passivating, and patterning properties of the ORMOCER materials, these devices lay the foundation for a new generation of high-quality, fast, processable low-cost organic electronics

Organic nanoparticle dispersions are prepared via a versatile technique. Particles are formed by evaporation of aromatic hydrocarbons (like pentacene, rubrene, and tetracene) in an inert atmosphere and condensation of the vapor in a liquid medium. This allows the preparation of stable and concentrated dispersions of organic nanoparticles, showing interesting optical properties and potential applications in organic electronics and sensors.

In this contribution, we present two flexible thiol-ene-based hybrid materials based on epoxy and acetoxy polysiloxane matrix materials. The latter cross-linking mechanisms allow for orthogonal curing of the matrix in the presence of thiol-ene monomers enabling fast one-step access to two-photon-polymerization (2PP) curable substrates for waveguide fabrication. Another time-saving feature of our concept is the straightforward UV-flood-curing after 2PP, which is also a progress compared to previous works with elaborate postprocessing. Optimization of the ratio of thiol/ene moieties with respect to reactivity and analyses of the thermal stability of the materials, which is required for the industrial process, were carried out. Besides investigations regarding the refractive index of the materials, the proof of principle for successful waveguiding will be given. Flexible optical waveguides were successfully fabricated inside a low refractive polysiloxane matrix material.