2011/09/14 by Olga Wodo, Wodo, Olga, Baskar Ganapathysubramanian +1 · 3 citations
Engineering · Materials Science · #Block Copolymer Self-Assembly #FOS: Physical sciences #Fluid Dynamics and Thin Films #Mathematical Physics (math-ph) #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Organic Electronics and Photovoltaics
paper · pdf · doi:10.48550/arxiv.1109.3239
openalex publication_date 2011/09/14 · openalex created_date 2022/09/27 · openalex updated_date 2026/07/28
Solvent-based techniques usually involve preparing dilute blends of\nelectron-donor and electron-acceptor materials dissolved in a volatile solvent.\nAfter some form of coating onto a substrate, the solvent evaporates. An\ninitially homogeneous mixture separates into electron-acceptor rich and\nelectron-donor rich regions as the solvent evaporates. Depending on the\nspecifics of the blend and processing conditions different morphologies are\ntypically formed. Experimental evidence consistently confirms that the\nmorphology critically affects device performance. A computational framework\nthat can predict morphology evolution can significantly augment experimental\nanalysis. Such a framework will also allow high throughput analysis of the\nlarge phase space of processing parameters, thus yielding insight into the\nprocess-structure-property relationships.\n In this paper, we formulate a computational framework to predict evolution of\nmorphology during solvent-based fabrication of organic thin films. This is\naccomplished by developing a phase field-based model of evaporation-induced and\nsubstrate-induced phase-separation in ternary systems. This formulation allows\nall the important physical phenomena affecting morphology evolution during\nfabrication to be naturally incorporated. We discuss the various numerical and\ncomputational challenges associated with a three dimensional, finite-element\nbased, massively parallel implementation of this framework. This formulation\nallows, for the first time, to model 3D morphology evolution over large time\nspans on device scale domains. We illustrate this framework by investigating\nand quantifying the effect of various process and system variables on\nmorphology evolution. We explore ways to control the morphology evolution by\ninvestigating different evaporation rates, blend ratios and interaction\nparameters between components.\n