Journal article
Effect of Defective Microstructure and Film Thickness on the Reflective Structural Color of Self-Assembled Colloidal Crystals
ACS applied materials & interfaces, v 12(8), pp 9842-9850
26 Feb 2020
PMID: 31990514
Abstract
Structural color arises from geometric diffraction; it has potential applications in optical materials because it is more resistant to environmental degradation than coloration mechanisms that are of chemical origin. Structural color can be produced from self-assembled films of colloidal size particles. While the relationship between the crystal structure and structural color reflection peak wavelength is well studied, the connection between assembly quality and the degree of reflective structural color is less understood. Here, we study this connection by investigating the structural color reflection peak intensity and width as a function of defect density and film thickness using a combined experimental and computational approach. Polystyrene microspheres are self-assembled into defective colloidal crystals via solvent evaporation. Colloidal crystal growth via sedimentation is simulated with molecular dynamics, and the reflection spectra of simulated structures are calculated by using the finite-difference time-domain algorithm. We examine the impact of commonly observed defect types (vacancies, stacking fault tetrahedra, planar faults, and microcracks) on structural color peak intensity. We find that the reduction in peak intensity scales with increased defect density. The reduction is less sensitive to the type of defect than to its volume. In addition, the reflectance of structural color increases as a function of the crystal thickness, until a plateau is reached at thicknesses greater than about 9.0 mu m. The maximum reflection is 78.8 +/- 0.9%; this value is significantly less than the 100% reflectivity predicted for a fully crystalline, defect-free material. Furthermore, we find that colloidal crystal films with small quantities of defects may be approximated as multilayer reflective materials. These findings can guide the design of optical materials with variable structural color intensity.
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Details
- Title
- Effect of Defective Microstructure and Film Thickness on the Reflective Structural Color of Self-Assembled Colloidal Crystals
- Creators
- Tianyu Liu - University of Michigan–Ann ArborBryan VanSaders - University of Michigan–Ann ArborSharon C. Glotzer - University of Michigan–Ann ArborMichael J. Solomon - University of Michigan–Ann ArborUniv. of Michigan, Ann Arbor, MI (United States)
- Publication Details
- ACS applied materials & interfaces, v 12(8), pp 9842-9850
- Publisher
- Amer Chemical Soc
- Number of pages
- 9
- Grant note
- University of Michigan Rackham Predoctoral Fellowship; University of Michigan System Advanced Research Computing at the University of Michigan, Ann Arbor DE-SC0013562 / Department of Energy, Basic Energy Sciences; United States Department of Energy (DOE)
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Physics
- Web of Science ID
- WOS:000517360000094
- Scopus ID
- 2-s2.0-85081168107
- Other Identifier
- 991021877482604721
InCites Highlights
Data related to this publication, from InCites Benchmarking & Analytics tool:
- Web of Science research areas
- Materials Science, Multidisciplinary
- Nanoscience & Nanotechnology