Anke Teichler

Inkjet printing of organic electronics – comparison of deposition techniques and state-of-the-art developments

Inkjet printing represents a solution dispensing technique that is characterized by its non-contact, material-efficient and reproducible processing. This critical review discusses the use of inkjet printing for organic electronics with a focus on the applicability as well as the drying behavior. The nascent inkjet printing technique is compared to commonly used solution deposition methods, like spin-coating and doctor blading. Basic drying principles of inkjet printed features are understood and fundamental correlations between processing properties and film characteristics can be drawn. It is, however, a long way to gain a full understanding of the complete drying process, since the process conditions as well as the ink properties correlate in a complex relation with the final device properties. Nevertheless, inkjet printing has the potential to evolve as one of the most promising film preparation techniques in the future and has already been applied successfully in combinatorial screening workflows and for the preparation of organic solar cell devices.

Localized atmospheric plasma sintering of inkjet printed silver nanoparticles

Atmospheric pressure argon plasma sintering of silver nanoparticle inks was investigated to improve the plasma sintering process in terms of sintering speed, substrate friendliness and technical complexity. Sintering times were reduced to several seconds while achieving similar conductivity values of above 10% compared to bulk silver. Sintering can be carried out under ambient conditions at specific locations without exposing the entire substrate. Plasma sintering at atmospheric pressure exhibits the capability to be used in roll-to-roll production processes.

Combinatorial screening of inkjet printed ternary blends for organic photovoltaics: absorption behavior and morphology.

Inkjet printing was used for the preparation of ternary polymer/polymer/fullerene layers for organic solar cell application, as part of a combinatorial setup for the preparation and characterization of thin-film libraries. Poly(phenylene-ethynylene)-alt-poly(phenylene-vinylene) (PPE-alt-PPV) and poly(diketopyrrolopyrrole-alt-fluorene) (P(DPP-alt-F)) were systematically blended with poly(3-octylthiophene) (P3OT) and investigated by UV-vis spectroscopy to improve the photon harvesting by extending the absorption range. The blends with the broadest absorption range (20 and 40 wt % of PPE-alt-PPV and P(DPP-alt-F), respectively) were mixed with mono(1-[3-(methoxycarbonyl)propyl]-1-phenyl)-[6,6]C61 (PCBM). The blend with the low band gap polymer P(DPP-alt-F) revealed the most extended absorption, which ranges over the whole visible spectrum (350 to 750 nm). The mixing with PCBM (ratio 1/3) led to an optimal emission quenching and revealed a smooth film formation. In this contribution, we show that the combinatorial screening using inkjet printing represents an effective, time- and material-saving workflow for the investigation of polymer blend libraries, which is of high interest for the development of new materials for active layers in organic photovoltaics.