Self-assembled multi-layer simple cubic photonic crystals of oppositely charged colloids in confinement
Designing and fabricating self-assembled open colloidal crystals have become one major direction in the soft matter community because of many promising applications associated with open colloidal crystals. However, most of the self-assembled crystals found in experiments are not open but close-packe...
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sg-ntu-dr.10356-1502262021-06-04T03:41:33Z Self-assembled multi-layer simple cubic photonic crystals of oppositely charged colloids in confinement Sankaewtong, Krongtum Lei, Qun-li Ni, Ran School of Chemical and Biomedical Engineering Engineering::Chemical engineering Crystalline Materials Energy Gap Designing and fabricating self-assembled open colloidal crystals have become one major direction in the soft matter community because of many promising applications associated with open colloidal crystals. However, most of the self-assembled crystals found in experiments are not open but close-packed. Here, by using computer simulation, we systematically investigate the self-assembly of oppositely charged colloidal hard spheres confined between two parallel hard walls, and we find that the confinement can stabilize multi-layer NaCl-like (simple cubic) open crystals. The maximal number of layers of stable NaCl-like crystals increases with decreasing inverse screening length. More interestingly, at finite low temperature, the large vibrational entropy can stabilize some multi-layer NaCl-like crystals against the most energetically favoured close-packed crystals. In the parameter range studied, we find up to 4-layer NaCl-like crystals to be stable in confinement. Our photonic calculation shows that the inverse 4-layer NaCl-like crystal can already reproduce the large photonic band gaps of the bulk simple cubic crystal, which open in the low frequency range with a low dielectric contrast. This suggests new possibilities of using confined colloidal systems to fabricate open crystalline materials with novel photonic properties. Agency for Science, Technology and Research (A*STAR) Ministry of Education (MOE) Nanyang Technological University This work is supported by the Nanyang Technological University Start-Up Grant (NTU-SUG: M4081781.120), the Academic Research Fund from Singapore Ministry of Education (M4011616.120 and M4011873.120), and the Advanced Manufacturing and Engineering Young Individual Research Grant (A1784C0018) from the Science and Engineering Research Council of Agency for Science, Technology and Research, Singapore. 2021-06-04T03:41:33Z 2021-06-04T03:41:33Z 2019 Journal Article Sankaewtong, K., Lei, Q. & Ni, R. (2019). Self-assembled multi-layer simple cubic photonic crystals of oppositely charged colloids in confinement. Soft Matter, 15(15), 3104-3110. https://dx.doi.org/10.1039/c9sm00018f 1744-683X https://hdl.handle.net/10356/150226 10.1039/c9sm00018f 30810154 2-s2.0-85064174602 15 15 3104 3110 en M4081781.120 M4011616.120 M4011873.120 A1784C0018 Soft Matter © 2019 Royal Society of Chemistry. All rights reserved. |
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Engineering::Chemical engineering Crystalline Materials Energy Gap Sankaewtong, Krongtum Lei, Qun-li Ni, Ran Self-assembled multi-layer simple cubic photonic crystals of oppositely charged colloids in confinement |
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Designing and fabricating self-assembled open colloidal crystals have become one major direction in the soft matter community because of many promising applications associated with open colloidal crystals. However, most of the self-assembled crystals found in experiments are not open but close-packed. Here, by using computer simulation, we systematically investigate the self-assembly of oppositely charged colloidal hard spheres confined between two parallel hard walls, and we find that the confinement can stabilize multi-layer NaCl-like (simple cubic) open crystals. The maximal number of layers of stable NaCl-like crystals increases with decreasing inverse screening length. More interestingly, at finite low temperature, the large vibrational entropy can stabilize some multi-layer NaCl-like crystals against the most energetically favoured close-packed crystals. In the parameter range studied, we find up to 4-layer NaCl-like crystals to be stable in confinement. Our photonic calculation shows that the inverse 4-layer NaCl-like crystal can already reproduce the large photonic band gaps of the bulk simple cubic crystal, which open in the low frequency range with a low dielectric contrast. This suggests new possibilities of using confined colloidal systems to fabricate open crystalline materials with novel photonic properties. |
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School of Chemical and Biomedical Engineering |
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School of Chemical and Biomedical Engineering Sankaewtong, Krongtum Lei, Qun-li Ni, Ran |
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Article |
author |
Sankaewtong, Krongtum Lei, Qun-li Ni, Ran |
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Sankaewtong, Krongtum |
title |
Self-assembled multi-layer simple cubic photonic crystals of oppositely charged colloids in confinement |
title_short |
Self-assembled multi-layer simple cubic photonic crystals of oppositely charged colloids in confinement |
title_full |
Self-assembled multi-layer simple cubic photonic crystals of oppositely charged colloids in confinement |
title_fullStr |
Self-assembled multi-layer simple cubic photonic crystals of oppositely charged colloids in confinement |
title_full_unstemmed |
Self-assembled multi-layer simple cubic photonic crystals of oppositely charged colloids in confinement |
title_sort |
self-assembled multi-layer simple cubic photonic crystals of oppositely charged colloids in confinement |
publishDate |
2021 |
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https://hdl.handle.net/10356/150226 |
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1702431152972759040 |