论文标题
蒸发晶体多组分膜中形态形成的相位模拟
Phase-field simulations of the morphology formation in evaporating crystalline multicomponent films
论文作者
论文摘要
在许多溶液处理的薄膜中，在干燥或随后的加工步骤期间出现了由液 - 液相分离（LLP）或多结晶产生的复杂形态。形态对最终设备的性能有很大的影响，但不幸的是，过程结构关系通常很差，并且仅在定性上被理解。这是因为许多不同的物理机制（混溶，蒸发，结晶，扩散，对流）在潜在的时间尺度上活跃，并且动力学起着至关重要的作用：形态发展为直到动力学远离平衡。为了揭示各种可能的结构形成途径，我们提出了一个统一的理论框架，该框架考虑了所有这些物理现象。此相位模拟工具基于用于扩散的Cahn-Hilliard方程，以及用于结晶和蒸发的艾伦-CAHN方程，它们与流体动力学的方程式耦合。我们根据简单的测试用例讨论并验证耦合模型的行为。此外，我们说明了该框架如何允许研究蒸发诱导的LLP和结晶的干燥膜中的形态形成，这通常是遇到的情况，例如在有机光伏应用中。
In numerous solution-processed thin films, a complex morphology resulting from liquid-liquid phase separation (LLPS) or from polycrystallization arises during the drying or subsequent processing steps. The morphology has a strong influence on the performance of the final device but unfortunately the process-structure relationship is often poorly and only qualitatively understood. This is because many different physical mechanisms (miscibility, evaporation, crystallization, diffusion, advection) are active at potentially different time scales, and because the kinetics plays a crucial role: the morphology develops until it is kinetically quenched far from equilibrium. In order to unravel the various possible structure formation pathways, we propose a unified theoretical framework that takes into account all these physical phenomena. This phase-field simulation tool is based on the Cahn-Hilliard equations for diffusion and the Allen-Cahn equation for crystallization and evaporation, which are coupled to the equations for the dynamics of the fluid. We discuss and verify the behavior of the coupled model based on simple test cases. Furthermore, we illustrate how this framework allows to investigate the morphology formation in a drying film undergoing evaporation-induced LLPS and crystallization, which is typically a situation encountered, e.g., in organic photovoltaics applications.
