Simulations of Morphology Evolution in Polymer Blends during Light Self-Trapping

Physica Status Solidi (a)

2018

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The authors report on the enhancement in optical energy conversion in silicon solar cells encapsulated with a polymer film comprising of waveguide array structures. The structures are fabricated through light-induced selfwriting with periodic arrangements of optical beams transmitted through a binary component photopolymer, wherein a periodic core-cladding architecture is produced. The size, spacing, and arrangement of the cores are varied through the size and arrangement of the optical beams via photomask design. A range of waveguide array structures are produced using different masks and component weight fractions. External quantum efficiency (EQE) measurements reveal structures that provide the greatest enhancement for normal and non-normal incidence irradiation, the latter for which reveals wide-angle light capture and conversion. Encapsulated solar cells yield an approximate 10% enhancement in EQE and a 20% increase in the short circuit current, up to an incident angle of 40 , as compared to uniform encapsulants. The experimental results are corroborated by beam propagation simulations that show the spatial confinement of transmitted optical energy is the main effect that increases conversion efficiency. Principles that establish a structure-property-performance relationship are discussed, toward rational materials processing to increase energy conversion.

Section: Resultsmentioning

confidence: 99%

“…Simulations of Light Transmission : Theoretical light collection was determined from simulations of light transmission in a model 2D array of cylindrical waveguides. The waveguides were assumed to have a refractive index of cured NOA65 for the core, and cladding with a refractive index of cured PDMS.…”

Section: Methodsmentioning

confidence: 99%

Enhanced Wide‐Angle Energy Conversion Using Structure‐Tunable Waveguide Arrays as Encapsulation Materials for Silicon Solar Cells

Biria

Chen

Physica Status Solidi (a)

2018

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“…Photo-cross-linking is not specifically indicated in the equation to some extent by f , but rather by varying the relative weight fraction of the polyfunctional monomer the extent of cross-linking can be varied, and greater fractions will induce greater cross-linking and inhibit the components from separating. Simulations of the process all revealed this competition over a range of parameters . Overall there still remain several studies to be performed on the underlying determinative factors and how they affect the attainment of correlated morphologies.…”

Section: Recent Work On Self-trapping and Self-writing Polymer Materialsmentioning

confidence: 95%

Light-Directed Organization of Polymer Materials from Photoreactive Formulations

2020

Chem. Mater.

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This perspective presents a recently developed approach to organize polymer and polymer composite materials through a new form of light-directed organization of photoreactive polymeric media. Under suitable conditions, such media will interact with light, in a mutual dynamic process, that results in the spontaneous organization of both the input light field and, importantly, the polymer media. New material structures can be created in free-radical-initiated media, polymer blends and polymer−solvent mixtures, as well as possibly more complex, multicomponent formulations. An overview of the underlying principles and chemical phenomena and exemplary material structures are presented. Materials produced using this new processing approach can be used as functional coatings, textured surfaces, and membranes, as well as a host of other applications via selection of polymer composition. Key open questions and areas for further inquiry and advancement are presented. Coupling the dynamics of light pattern formation processes to photoreactive matter is a promising new approach to the organization of materials for a range of critical applications and reveals interesting nonlinear dynamic phenomena in the organization of materials.

“…Full details of the multiphysics simulation framework can be found in our previous study. 33 Brief descriptions of the different phenomena are described herein.…”

Section: Methodsmentioning

confidence: 99%

“…We have previously established a multiphysics simulation framework for photoreactive polymer blends that combines the multiple phenomena entailed in the self-trapping/self-focusing of an optical beam, photopolymerization kinetics, and phase separation in the proximity of the optical beam, whereby polymer blend morphology could be theoretically predicted and mapped over a range of polymer blends, growth kinetics, and thermodynamic parameters. 33 In this study, we employ this multiphysics simulation framework to now theoretically investigate the evolution of structure and morphology in photoreactive polymer blends under irradiation with arrays of intersecting beams. The study herein leverages our established multiphysics framework to now particularly examine the implication of the construction of complex morphologies and structures using multiple, intersecting optical beams and the dependencies of the blend and processing parameters enabling the optical beams to pattern binary phase morphology into a 3D structure.…”

Section: Introductionmentioning

confidence: 99%

Simulations of Structure and Morphology in Photoreactive Polymer Blends under Multibeam Irradiation

Ding

2022

J. Phys. Chem. C

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We present a theoretical study of the organization of photoreactive polymer blends under irradiation by multiple arrays of intersecting optical beams. In a simulated medium possessing an integrated intensity-dependent refractive index, optical beams undergo self-focusing and reduced divergence. A corresponding intensity-dependent increase in molecular weight induces polymer blend instability and consequent phase separation, whereby the medium can evolve into an intersecting waveguide lattice structure, comprising high refractive index cylindrical cores and a surrounding low refractive index medium (cladding). We conduct simulations for two propagation angles and a range of thermodynamic, kinetic, and polymer blend parameters to establish correlations to structure and morphology. We show that spatially correlated structures, namely, those that have a similar intersecting three-dimensional (3D) pattern as the arrays of intersecting optical beams, are achieved via a balance between the competitive processes of photopolymerization rate and phase separation dynamics. A greater intersection angle of the optical beams leads to higher correlations between structures and the optical beam pattern and a wider parameter space that achieves correlated structures. This work demonstrates the potential to employ complex propagating light patterns to create 3D organized structures in multicomponent photoreactive soft systems.