Biomass gasification at temperatures below 1300°C yields producer gas with a range of heavy hydrocarbons. These compounds, collectively known as tar, cause fouling and emission problems in equipment using the producer gas. This paper gives an overview of the work performed at the Energy research Centre of The Netherlands (ECN) on tar measurement, tar prevention, tar cracking, and tar removal. Much of the work has been performed in cooperation with partner institutes and industry. Measurement techniques discussed are the tar guideline, solid-phase adsorption (SPA) method, and tar dew point analyzer. On the subject of tar prevention, the effects of operating conditions, fuel composition, and bed materials in fluidized-bed gasifiers are covered. Tar cracking results are presented for catalytic materials, hightemperature treatment, and the use of plasma. ECN research on tar removal involves among others the development of the water-based GASREIP system and the oil-based OLGA technique.
The large volume production of flexible electronics by solution based roll-to-roll (R2R) manufacturing technologies is a promising upscaling strategy for the organic electronics industry. Typical optoelectronic devices like organic light emitting diodes (OLEDs) consist of a complex stack of functional layers. Solution deposition of these structures eliminates the need for expensive vacuum processing. This contribution presents approaches for solution based R2R production methods of functional OLED layers on flexible polymer substrates. The development of a R2R line with two slot-die coating stations is discussed which can deposit two uniform layers consecutively in a single run ("tandem coating") at web speeds up to 30 m/min. Furthermore, it offers the unique feature that there is no contact between the rollers and the top side of the substrate where the functional coating is deposited. Thereby, an important source of particle contamination and other damage to the device is eliminated. In addition to continuous deposition, stripe and intermittent coating techniques have been developed, allowing the production of patterned layers. Finally, examples will be shown of OLEDs where two functional materials are deposited by R2R processing from solution.
To develop a detailed understanding about halide perovskite processing from solution, the crystallization processes are investigated during spin coating and slot‐die coating of MAPbI3 at different evaporation rates by simultaneous in situ photoluminescence, light scattering, and absorption measurements. Based on the time evolution of the optical parameters it is found that for both processing methods initially solvent‐complex‐structures form, followed by perovskite crystallization. The latter proceeds in two stages for spin coating, while for slot‐die coating only one perovskite crystallization phase occurs. For both processing methods, it is found that with increasing evaporation rates, the crystallization kinetics of the solvent‐complex structure and the perovskite crystallization remain constant on a relative time scale, whereas the duration of the second perovskite crystallization in spin coating increases. This second perovskite crystallization appears restricted due to differences in solvent‐complex phase morphologies from which the perovskite forms. The work emphasizes the importance of the exact precursor state properties on the perovskite formation. It further demonstrates that detailed analyses of multimodal optical in situ spectroscopy allows gaining a fundamental understanding of the crystallization processes that take place during solution processing of halide perovskites, independent from the specific processing method.
An anti-solvent free facile solution processing technique for fabricating perovskite light emitting diodes (PeLEDs), and scaling it up to large areas by slot-die coating.
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