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Lai CF, Lin CP, Lee YC. Enhancement of Light Efficiency of Deep-Ultraviolet Light-Emitting Diodes by Encapsulation with a 3D Photonic Crystal Reflecting Layer. NANOMATERIALS (BASEL, SWITZERLAND) 2024; 14:983. [PMID: 38869608 PMCID: PMC11173468 DOI: 10.3390/nano14110983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Revised: 05/28/2024] [Accepted: 06/04/2024] [Indexed: 06/14/2024]
Abstract
Recently, UVC LEDs, which emit deep ultraviolet light, have found extensive applications across various fields. This study demonstrates the design and implementation of thin films of three-dimensional photonic crystals (3D PhCs) as reflectors to enhance the light output power (LOP) of UVC LEDs. The 3D PhC reflectors were prepared using the self-assembly of silica nanospheres on a UVC LED lead frame substrate via the evaporation-induced method (side) and the gravitational sedimentation method (bottom), respectively. These PhCs with the (111) crystallographic plane were deposited on the side wall and bottom of the UVC LED lead frame, acting as functional materials to reflect UVC light. The LOP of UVC LEDs with 3D PhC reflectors at a driving current of 100 mA reached 19.6 mW. This represented a 30% enhancement compared to commercial UVC LEDs with Au-plated reflectors, due to the UVC light reflection by the photonic band gaps of 3D PhCs in the (111) crystallographic plane. Furthermore, after aging tests at 60 °C and 60% relative humidity for 1000 h, the relative LOP of UVC LEDs with 3D PhC reflectors decreased by 7%, which is better than that of commercial UVC LEDs. Thus, this study offers potential methods for enhancing the light output efficiency of commercial UVC light-emitting devices.
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Affiliation(s)
- Chun-Feng Lai
- Department of Photonics, Feng Chia University, Taichung 407, Taiwan
| | - Chun-Peng Lin
- Lextar Electronics Corp., Hsinchu Science Park, Hsinchu 30075, Taiwan; (C.-P.L.); (Y.-C.L.)
| | - Yu-Chun Lee
- Lextar Electronics Corp., Hsinchu Science Park, Hsinchu 30075, Taiwan; (C.-P.L.); (Y.-C.L.)
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2
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Nam K, Lee DY. Self-Organization via Dewetting in Polymeric Assemblies. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2400255. [PMID: 38597696 DOI: 10.1002/smll.202400255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 03/08/2024] [Indexed: 04/11/2024]
Abstract
Dewetting is a spontaneous process involving a thin liquid film that minimizes interfacial energy by reducing the surface area via the generation of defects on the film. In industry, dewetting is regarded as a problem that results in defects or a heterogeneous surface; however, in this study, dewetting is intentionally induced to create various patterns at intended positions spontaneously with polymeric materials and nanoparticles. The dewetting-induced patterning process is conducted by controlling the capillary force and evaporation ratio through an evaporative self-assembly system. The linear-polymeric arrays on the substrate played an important role in modifying the surface geometry and treatment for a heterogeneous surface, and an additional patterning process is performed on patterned arrays to create dewetting-induced self-organizing patterns. Here, this method is used to introduce material arrays with specific shapes such as dots, dumbbells, potbellies, Vs, and trapezoids.
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Affiliation(s)
- Kibeom Nam
- Department of Polymer Science and Engineering, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Dong Yun Lee
- Department of Polymer Science and Engineering, Kyungpook National University, Daegu, 41566, Republic of Korea
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3
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Han JH, Shneidman AV, Kim DY, Nicolas NJ, Hoeven JES, Aizenberg M, Aizenberg J. Highly Ordered Inverse Opal Structures Synthesized from Shape‐Controlled Nanocrystal Building Blocks. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202111048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Jae Hyo Han
- Department of Chemistry and Chemical Biology & John A. Paulson School of Engineering and Applied Sciences Harvard University 29 Oxford St. Cambridge MA 02138 USA
| | - Anna V. Shneidman
- John A. Paulson School of Engineering and Applied Sciences Harvard University 29 Oxford St. Cambridge MA 02138 USA
| | - Do Yoon Kim
- John A. Paulson School of Engineering and Applied Sciences Harvard University 29 Oxford St. Cambridge MA 02138 USA
| | - Natalie J. Nicolas
- John A. Paulson School of Engineering and Applied Sciences Harvard University 29 Oxford St. Cambridge MA 02138 USA
| | - Jessi E. S. Hoeven
- Department of Chemistry and Chemical Biology & John A. Paulson School of Engineering and Applied Sciences Harvard University 29 Oxford St. Cambridge MA 02138 USA
| | - Michael Aizenberg
- John A. Paulson School of Engineering and Applied Sciences Harvard University 29 Oxford St. Cambridge MA 02138 USA
| | - Joanna Aizenberg
- Department of Chemistry and Chemical Biology & John A. Paulson School of Engineering and Applied Sciences Harvard University 29 Oxford St. Cambridge MA 02138 USA
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4
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Han JH, Shneidman AV, Kim DY, Nicolas NJ, van der Hoeven JES, Aizenberg M, Aizenberg J. Highly Ordered Inverse Opal Structures Synthesized from Shape-Controlled Nanocrystal Building Blocks. Angew Chem Int Ed Engl 2021; 61:e202111048. [PMID: 34606677 DOI: 10.1002/anie.202111048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/27/2021] [Indexed: 01/29/2023]
Abstract
Three-dimensional ordered porous materials known as inverse opal films (IOFs) were synthesized using nanocrystals with precisely defined morphologies. Comprehensive theoretical and experimental studies of the volume fraction ratio and electrostatic interactions between nanocrystals and polystyrene templating particles enabled the formation of highly ordered crack-free photonic structures. The synthetic strategy was first demonstrated using titanium dioxide (TiO2 ) nanocrystals of different shapes and then generalized to assemble nanocrystals of other functional materials, such as indium tin oxide and zinc-doped ferrite. Tunable photocatalytic activity of the TiO2 IOFs, modulated through the choice of the shape of TiO2 nanocrystals in conjunction with selecting desired macroscopic features of the IOF, was further explored. In particular, enhanced activity is observed for crack-free, highly ordered IOFs whose photonic properties can improve light absorption via the slow light effect. This study opens new opportunities in designing multi-length-scale porous nanoarchitectures having enhanced performance in a variety of applications.
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Affiliation(s)
- Jae Hyo Han
- Department of Chemistry and Chemical Biology &, John A. Paulson School of Engineering and Applied Sciences, Harvard University, 29 Oxford St., Cambridge, MA 02138, USA
| | - Anna V Shneidman
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, 29 Oxford St., Cambridge, MA, 02138, USA
| | - Do Yoon Kim
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, 29 Oxford St., Cambridge, MA, 02138, USA
| | - Natalie J Nicolas
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, 29 Oxford St., Cambridge, MA, 02138, USA
| | - Jessi E S van der Hoeven
- Department of Chemistry and Chemical Biology &, John A. Paulson School of Engineering and Applied Sciences, Harvard University, 29 Oxford St., Cambridge, MA 02138, USA
| | - Michael Aizenberg
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, 29 Oxford St., Cambridge, MA, 02138, USA
| | - Joanna Aizenberg
- Department of Chemistry and Chemical Biology &, John A. Paulson School of Engineering and Applied Sciences, Harvard University, 29 Oxford St., Cambridge, MA 02138, USA
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5
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Howard MP, Reinhart WF, Sanyal T, Shell MS, Nikoubashman A, Panagiotopoulos AZ. Evaporation-induced assembly of colloidal crystals. J Chem Phys 2018; 149:094901. [DOI: 10.1063/1.5043401] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Affiliation(s)
- Michael P. Howard
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Wesley F. Reinhart
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Tanmoy Sanyal
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, California 93106, USA
| | - M. Scott Shell
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, California 93106, USA
| | - Arash Nikoubashman
- Institute of Physics, Johannes Gutenberg University Mainz, Staudingerweg 7, 55128 Mainz, Germany
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Lee WC, Kim BH, Choi S, Takeuchi S, Park J. Liquid Cell Electron Microscopy of Nanoparticle Self-Assembly Driven by Solvent Drying. J Phys Chem Lett 2017; 8:647-654. [PMID: 28094948 DOI: 10.1021/acs.jpclett.6b02859] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Drying a colloidal solution of nanoparticles is a versatile method to construct self-assembled structures of nanoparticles. However, mechanistic understanding has mostly relied on empirical knowledge obtained from the final structures of self-assembly as relevant processes during solvent drying are likely kinetic and far from equilibrium. Here, we present in situ TEM studies of nanoparticle self-assembly under various conditions, including the concentrations of the initial solution and the types of nanoparticles and substrates. The capability of tracking trajectories of individual nanoparticles enables us to understand the mechanisms of drying-mediated self-assembly at the single-nanoparticle level. Our results consistently show that a solvent boundary primarily affects nanoparticle motions and the resulting self-assembly processes regardless of different conditions. The solvent boundary drives nanoparticles to form two-dimensional assembly mainly through two pathways, transporting scattered nanoparticles by lateral dragging and flattening aggregated nanoparticles by vertical pressing.
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Affiliation(s)
- Won Chul Lee
- Department of Mechanical Engineering, Hanyang University , Ansan, Gyeonggi 15588, Republic of Korea
- Institute of Industrial Science, The University of Tokyo , Tokyo 153-8505, Japan
- ERATO Takeuchi Biohybrid Innovation Project, Japan Science and Technology Agency , Tokyo 153-8904, Japan
| | - Byung Hyo Kim
- Center for Nanoparticle Research, Institute for Basic Science (IBS) , Seoul 08826, Republic of Korea
- School of Chemical and Biological Engineering, Seoul National University , Seoul 08826, Republic of Korea
| | - Sun Choi
- Center for Urban Energy Research, Korea Institutes of Science and Technology , Seoul 02792, Republic of Korea
| | - Shoji Takeuchi
- Institute of Industrial Science, The University of Tokyo , Tokyo 153-8505, Japan
- ERATO Takeuchi Biohybrid Innovation Project, Japan Science and Technology Agency , Tokyo 153-8904, Japan
| | - Jungwon Park
- Center for Nanoparticle Research, Institute for Basic Science (IBS) , Seoul 08826, Republic of Korea
- School of Chemical and Biological Engineering, Seoul National University , Seoul 08826, Republic of Korea
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Mino Y, Watanabe S, Miyahara MT. In situ observation of meniscus shape deformation with colloidal stripe pattern formation in convective self-assembly. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:4121-4128. [PMID: 25831052 DOI: 10.1021/acs.langmuir.5b00467] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Vertical convective self-assembly is capable of fabricating stripe-patterned structures of colloidal particles with well-ordered periodicity. To unveil the mechanism of the stripe pattern formation, in the present study, we focus on the meniscus shape and conduct in situ observations of shape deformation associated with particulate line evolution. The results reveal that the meniscus is elongated downward in a concave fashion toward the substrate in accordance with solvent evaporation, while the concave deformation is accelerated by solvent flow, resulting in the rupture of the liquid film at the thinnest point of the meniscus. The meniscus rupture triggers the meniscus to slide off from the particulate line, followed by the propagation of the sliding motion of the three-phase contact line, resulting in the formation of stripe spacing.
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Affiliation(s)
- Yasushi Mino
- Department of Chemical Engineering, Kyoto University, Katsura, Nishikyo, Kyoto 615-8510, Japan
| | - Satoshi Watanabe
- Department of Chemical Engineering, Kyoto University, Katsura, Nishikyo, Kyoto 615-8510, Japan
| | - Minoru T Miyahara
- Department of Chemical Engineering, Kyoto University, Katsura, Nishikyo, Kyoto 615-8510, Japan
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Lin D, Wang J, Yang L, Luo Y, Li D, Meng Q. Real-time synchronous CCD camera observation and reflectance measurement of evaporation-induced polystyrene colloidal self-assembly. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:3949-3956. [PMID: 24650361 DOI: 10.1021/la404778p] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A new monitoring technique, which combines real-time in-situ CCD camera observation and reflectance spectra measurement, has been developed to study the growing and drying processes of evaporation-induced self-assembly (EISA). Evolutions of the reflectance spectrum and CCD camera images both reveal that the entire process of polystyrene (PS) EISA contains three stages: crack-initiation stage (T1), crack-propagation stage (T2), and crack-remained stage (T3). A new phenomenon, the red-shift of stop-band, is observed when the crack begins to propagate in the monitored window of CCD camera. Deformation of colloidal spheres, which mainly results in the increase of volume fraction of spheres, is applied to explain the phenomenon. Moreover, the modified scalar wave approximation (SWA) is utilized to analyze the reflectance spectra, and the fitting results are in good agreement with the evolution of CCD camera images. This new monitoring technique and the analysis method provide a good way to get insight into the growing and drying processes of PS colloidal self-assembly, especially the crack propagation.
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Affiliation(s)
- Dongfeng Lin
- Key Laboratory for Renewable Energy, Chinese Academy of Sciences; Beijing Key Laboratory for New Energy Materials and Devices; Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China
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Thiruvengadathan R, Korampally V, Ghosh A, Chanda N, Gangopadhyay K, Gangopadhyay S. Nanomaterial processing using self-assembly-bottom-up chemical and biological approaches. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2013; 76:066501. [PMID: 23722189 DOI: 10.1088/0034-4885/76/6/066501] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Nanotechnology is touted as the next logical sequence in technological evolution. This has led to a substantial surge in research activities pertaining to the development and fundamental understanding of processes and assembly at the nanoscale. Both top-down and bottom-up fabrication approaches may be used to realize a range of well-defined nanostructured materials with desirable physical and chemical attributes. Among these, the bottom-up self-assembly process offers the most realistic solution toward the fabrication of next-generation functional materials and devices. Here, we present a comprehensive review on the physical basis behind self-assembly and the processes reported in recent years to direct the assembly of nanoscale functional blocks into hierarchically ordered structures. This paper emphasizes assembly in the synthetic domain as well in the biological domain, underscoring the importance of biomimetic approaches toward novel materials. In particular, two important classes of directed self-assembly, namely, (i) self-assembly among nanoparticle-polymer systems and (ii) external field-guided assembly are highlighted. The spontaneous self-assembling behavior observed in nature that leads to complex, multifunctional, hierarchical structures within biological systems is also discussed in this review. Recent research undertaken to synthesize hierarchically assembled functional materials have underscored the need as well as the benefits harvested in synergistically combining top-down fabrication methods with bottom-up self-assembly.
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10
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Guo W, Wang M, Xia W, Dai L. Two substrate-confined sol-gel coassembled ordered macroporous silica structures with an open surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:5944-5951. [PMID: 23614663 DOI: 10.1021/la304268b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A sol-gel cooperative assembly method was demonstrated for the fabrication of inverse opal films with an open surface. In this method, a sol-gel silicate precursor was cooperatively assembled into the interstitial spaces of microspheres at the same time when polystyrene templates formed in between two desired substrates. Silica inverse opals with a three-dimensional ordered macroporous (3DOM) structure were obtained after selective removing the colloidal templates by calcination. The open surfaces with a high degree of interconnected porosity and extremely uniform pore size were characterized by scanning electron microscope (SEM). Optical transmission spectra reveals the existence of considerable deep band gaps of up to 70% and steep band edges of up to 6%/nm in the [111] directions of the 3DOM silica samples. A little shrinkage confirmed by transmission spectra is not larger than 3%, in consistent with the results measured by SEM, which revealing the sufficient and compact infiltration into the interstitial spaces by our confined sol-gel coassembly method. With different incidence angles, the positions of pseudogaps can be easily tuned in the wide range from 720 nm to 887 nm, agreed well with the calculated values by the Bragg law. All the results prove that the sol-gel coassembly method with two substrates confinement is a simple, low cost, convenient and versatile method for the fabrication of silica inverse opals without overlayers in large domains.
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Affiliation(s)
- Wenhua Guo
- School of Physics and Technology, Nanjing Normal University, Key Laboratory on Opto-Electronic Technology of Jiangsu Province, Nanjing 210046, China
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11
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Lu C, Akey AJ, Dahlman CJ, Zhang D, Herman IP. Resolving the Growth of 3D Colloidal Nanoparticle Superlattices by Real-Time Small-Angle X-ray Scattering. J Am Chem Soc 2012; 134:18732-8. [DOI: 10.1021/ja307848h] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Chenguang Lu
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United
States
| | - Austin J. Akey
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United
States
| | - Clayton J. Dahlman
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United
States
| | - Datong Zhang
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United
States
| | - Irving P. Herman
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United
States
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12
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Yang L, Wang J, Zhang Y, Luo Y, Li D, Meng Q. In situ optical microspectroscopy monitoring of binary colloidal crystal growth dynamics via evaporation-induced cooperative self-assembly. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:4160-4167. [PMID: 22320329 DOI: 10.1021/la205111v] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Real-time monitoring of the binary colloidal crystal (bCC) growth via evaporation-induced cooperative self-assembly (EICSA) was studied by an in situ optical microspectroscopy technique. Evolution of the recorded reflectance spectra reveals that the whole growth process of bCCs via EICSA could be separated into three different stages corresponding to that of unary colloidal crystals because of the same evaporation model. We show the detailed cooperative self-assembly information, including the evolution of the number of layers and filling factors of different components of the growing bCCs using the scalar wave approximation method. Furthermore, when the size ratio and number ratio of the two colloids were varied, the real-time optical properties of the bCCs with various stoichiometric configurations were investigated systematically. This study would be valuable in furthering the current understanding of the bCC growth dynamics via EICSA and tailoring optical properties of hierarchical materials for applications in many fields.
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Affiliation(s)
- Lei Yang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, People's Republic of China
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Yang L, Zhang Y, Luo J, Luo Y, Gao K, Li D, Meng Q. Real-time studies of evaporation-induced colloidal self-assembly by optical microspectroscopy. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 84:031605. [PMID: 22060383 DOI: 10.1103/physreve.84.031605] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Revised: 07/20/2011] [Indexed: 05/31/2023]
Abstract
Real-time monitoring of the whole growth process of evaporation-induced colloidal self-assembly has been conducted using an optical microspectroscopy setup. Our observations suggest that the assembly process can be divided into three different growth stages as evidenced by the variations detected in the reflectance spectra. The thickness variation of the growing colloidal crystal was monitored by examining the Fabry-Perot fringes in the reflectance spectra. Furthermore, the scalar wave approximation was utilized to analyze the evolution of optical properties with growth. More detailed information, including the time dependence of number of layers and volume fraction of water, has been revealed by comparing the experimental and calculated reflectance spectra. The present work demonstrates that in situ real-time microspectroscopy is a promising technique for monitoring and investigating the dynamic process of colloidal self-assembly.
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Affiliation(s)
- Lei Yang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P. O. Box, 603, Beijing 100190, China
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