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The efficiency of organic bulk heterojunction solar cells strongly depends on the multiscale morphology of the interpenetrating polymer-fullerene network. Understanding the molecular assembly and the identification of influencing parameters is essential for a systematic optimization of such devices. Here, we investigate the molecular ordering during the drying of doctor-bladed polymer-fullerene blends on PEDOT:PSS-coated substrates simultaneously using in situ grazing incidence X-ray diffraction (GIXD) and laser reflectometry. In the process of blend crystallization, we observe the nucleation of well-aligned P3HT crystallites in edge-on orientation at the interface at the instant when P3HT solubility is crossed. A comparison of the real-time GIXD study at ternary blends with the binary phase diagrams of the drying blend film gives evidence of strong polymer-fullerene interactions that impede the crystal growth of PCBM, resulting in the aggregation of PCBM in the final drying stage. A systematic dependence of the film roughness on the drying time after crossing P3HT solubility has been shown. The highest efficiencies have been observed for slow drying at low temperatures which showed the strongest P3HT interchain π-π-ordering along the substrate surface. By adding the "unfriendly" solvent cyclohexanone to a chlorobenzene solution of P3HT:PCBM, the solubility can be crossed prior to the drying process. Such solutions exhibit randomly orientated crystalline structures in the freshly cast film which results in a large crystalline orientation distribution in the dry film that has been shown to be beneficial for solar cell performance.

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One essential process step during electrode processing for Li-ion batteries is the drying of the wet particulate electrode coating. The electrode film solidifies during evaporation of the solvent and a porous film is formed. In this study we focus on the influence of drying temperature on the internal electrode structure of the dry film. Anode slurries that consist of graphite and an aqueous binder system were coated and subsequently dried. To assure defined and controllable drying conditions, a laboratory set-up with a temperaturecontrolled substrate carrier and an impingement dryer was used. To facilitate a scale-up to continuously passed dryers the choice of experimental temperatures was based on a calculation of steady-state temperatures that result from gas temperatures that are commonly applied in industrial drying processes. The delamination behavior of the differently dried electrodes was investigated by means of a 90° peel test. The results show a strong dependency of electrode adhesion on drying temperature. A lower adhesion force at higher temperatures hints to a variation in binder content at the interface between the copper substrate and the coating layer. The formation of a consolidation Downloaded by [University of Manitoba Libraries] at 22:53 26 August 20152 layer at the air-film interface during drying is identified as a possible explanation and a criterion for consolidation layer formation is suggested.

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