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Khanyile BS, Numan N, Simo A, Nkosi M, Mtshali CB, Khumalo Z, Madiba IG, Mabakachaba B, Swart H, Coetsee-Hugo E, Duvenhage MM, Lee E, Henini M, Gibaud A, Chaker M, Rezaee P, Lethole N, Akbari M, Morad R, Maaza M. Towards Room Temperature Thermochromic Coatings with controllable NIR-IR modulation for solar heat management & smart windows applications. Sci Rep 2024; 14:2818. [PMID: 38307893 PMCID: PMC10837131 DOI: 10.1038/s41598-024-52021-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Accepted: 01/12/2024] [Indexed: 02/04/2024] Open
Abstract
Solar heat management & green air-conditioning are among the major technologies that could mitigate heat islands phenomenon while minimizing significantly the CO2 global foot-print within the building & automotive sectors. Chromogenic materials in general, and thermochromic smart coatings especially are promising candidates that consent a noteworthy dynamic solar radiation Infrared (NIR-IR) regulation and hence an efficient solar heat management especially with the expected increase of the global seasonal temperature. Within this contribution, two major challenging bottlenecks in vanadium oxide based smart coatings were addressed. It is validated for the first time that the NIR-IR modulation of the optical transmission (∆TTRANS = T(T〈TMIT) - T(T〉TMIT) of Vanadium oxide based smart coatings can be controlled & tuned. This upmost challenging bottle-neck controllability/tunability is confirmed via a genuine approach alongside to a simultaneous drastic reduction of the phase transition temperature TMIT from 68.8 °C to nearly room temperature. More precisely, a substantial thermochromism in multilayered V2O5/V/V2O5 stacks equivalent to that of standard pure VO2 thin films but with a far lower transition temperature, is reported. Such a multilayered V2O5/V/V2O5 thermochromic system exhibited a net control & tunability of the optical transmission modulation in the NIR-IR (∆TTRANS) via the nano-scaled thickness' control of the intermediate Vanadium layer. In addition, the control of ∆TTRANS is accompanied by a tremendous diminution of the thermochromic transition temperature from the elevated bulk value of 68.8 °C to the range of 27.5-37.5 ºC. The observed remarkable and reversible thermochromism in such multilayered nano-scaled system of V2O5/V/V2O5 is likely to be ascribed to a noteworthy interfacial diffusion, and an indirect doping by alkaline ions diffusing from the borosilicate substrate. It is hoped that the current findings would contribute in advancing thermochromic smart window technology and their applications for solar heat management in glass windows in general, skyscraper especially & in the automotive industry. If so, this would open a path to a sustainable green air-conditioning with zero-energy input.
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Affiliation(s)
- B S Khanyile
- MRD-Tandetron Accelerator & Nanosciences African Network, iThemba LABS-National Research Foundation, P O Box 722, Somerset West, 7129, Western Cape Province, South Africa.
- UNESCO-UNISA Africa Chair in Nanosciences and Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, P.O. Box 392, Pretoria, 003, South Africa.
| | - N Numan
- MRD-Tandetron Accelerator & Nanosciences African Network, iThemba LABS-National Research Foundation, P O Box 722, Somerset West, 7129, Western Cape Province, South Africa
- UNESCO-UNISA Africa Chair in Nanosciences and Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, P.O. Box 392, Pretoria, 003, South Africa
| | - A Simo
- MRD-Tandetron Accelerator & Nanosciences African Network, iThemba LABS-National Research Foundation, P O Box 722, Somerset West, 7129, Western Cape Province, South Africa
- UNESCO-UNISA Africa Chair in Nanosciences and Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, P.O. Box 392, Pretoria, 003, South Africa
| | - M Nkosi
- MRD-Tandetron Accelerator & Nanosciences African Network, iThemba LABS-National Research Foundation, P O Box 722, Somerset West, 7129, Western Cape Province, South Africa
- UNESCO-UNISA Africa Chair in Nanosciences and Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, P.O. Box 392, Pretoria, 003, South Africa
| | - C B Mtshali
- MRD-Tandetron Accelerator & Nanosciences African Network, iThemba LABS-National Research Foundation, P O Box 722, Somerset West, 7129, Western Cape Province, South Africa
| | - Z Khumalo
- MRD-Tandetron Accelerator & Nanosciences African Network, iThemba LABS-National Research Foundation, P O Box 722, Somerset West, 7129, Western Cape Province, South Africa
| | - I G Madiba
- MRD-Tandetron Accelerator & Nanosciences African Network, iThemba LABS-National Research Foundation, P O Box 722, Somerset West, 7129, Western Cape Province, South Africa
- UNESCO-UNISA Africa Chair in Nanosciences and Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, P.O. Box 392, Pretoria, 003, South Africa
| | - B Mabakachaba
- MRD-Tandetron Accelerator & Nanosciences African Network, iThemba LABS-National Research Foundation, P O Box 722, Somerset West, 7129, Western Cape Province, South Africa
- UNESCO-UNISA Africa Chair in Nanosciences and Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, P.O. Box 392, Pretoria, 003, South Africa
- Physics Department, University of the Western Cape, P.O. Box 1906, Bellville, 7535, South Africa
| | - H Swart
- Faculty of Natural and Agricultural Sciences, Physics Department, University of the Free State, P.O. Box 339, Bloemfontein, 9300, Republic of South Africa
| | - E Coetsee-Hugo
- Faculty of Natural and Agricultural Sciences, Physics Department, University of the Free State, P.O. Box 339, Bloemfontein, 9300, Republic of South Africa
| | - Mart-Mari Duvenhage
- Faculty of Natural and Agricultural Sciences, Physics Department, University of the Free State, P.O. Box 339, Bloemfontein, 9300, Republic of South Africa
| | - E Lee
- Faculty of Natural and Agricultural Sciences, Physics Department, University of the Free State, P.O. Box 339, Bloemfontein, 9300, Republic of South Africa
| | - M Henini
- School of Physics & Astronomy, Nottingham University, Nottingham, NG7 2RD7, UK
| | - A Gibaud
- IMMM, UMR 6283 CNRS, Bd O. Messiaen, University of Le Maine, 72085, Le Mans Cedex 09, France
| | - M Chaker
- INRS-Energie et Matériaux, 1650 Lionel-Boulet, Varennes, Québec, J3X 1S2, Canada
| | - P Rezaee
- MRD-Tandetron Accelerator & Nanosciences African Network, iThemba LABS-National Research Foundation, P O Box 722, Somerset West, 7129, Western Cape Province, South Africa
- UNESCO-UNISA Africa Chair in Nanosciences and Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, P.O. Box 392, Pretoria, 003, South Africa
| | - N Lethole
- Department Physics, University of Fort Hare, Alice, Eastern Cape Province, South Africa
| | - M Akbari
- MRD-Tandetron Accelerator & Nanosciences African Network, iThemba LABS-National Research Foundation, P O Box 722, Somerset West, 7129, Western Cape Province, South Africa
- UNESCO-UNISA Africa Chair in Nanosciences and Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, P.O. Box 392, Pretoria, 003, South Africa
| | - R Morad
- MRD-Tandetron Accelerator & Nanosciences African Network, iThemba LABS-National Research Foundation, P O Box 722, Somerset West, 7129, Western Cape Province, South Africa
- UNESCO-UNISA Africa Chair in Nanosciences and Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, P.O. Box 392, Pretoria, 003, South Africa
| | - M Maaza
- MRD-Tandetron Accelerator & Nanosciences African Network, iThemba LABS-National Research Foundation, P O Box 722, Somerset West, 7129, Western Cape Province, South Africa.
- UNESCO-UNISA Africa Chair in Nanosciences and Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, P.O. Box 392, Pretoria, 003, South Africa.
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Shi L, Wang H, Ma X, Wang Y, Wang F, Zhao D, Shen D. The Deformation Behavior and Bending Emissions of ZnO Microwire Affected by Deformation-Induced Defects and Thermal Tunneling Effect. SENSORS (BASEL, SWITZERLAND) 2021; 21:5887. [PMID: 34502777 PMCID: PMC8434524 DOI: 10.3390/s21175887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 11/16/2022]
Abstract
The realization of electrically pumped emitters at micro and nanoscale, especially with flexibility or special shapes is still a goal for prospective fundamental research and application. Herein, zinc oxide (ZnO) microwires were produced to investigate the luminescent properties affected by stress. To exploit the initial stress, room temperature in situ elastic bending stress was applied on the microwires by squeezing between the two approaching electrodes. A novel unrecoverable deformation phenomenon was observed by applying a large enough voltage, resulting in the formation of additional defects at bent regions. The electrical characteristics of the microwire changed with the applied bending deformation due to the introduction of defects by stress. When the injection current exceeded certain values, bright emission was observed at bent regions, ZnO microwires showed illumination at the bent region priority to straight region. The bent emission can be attributed to the effect of thermal tunneling electroluminescence appeared primarily at bent regions. The physical mechanism of the observed thermoluminescence phenomena was analyzed using theoretical simulations. The realization of electrically induced deformation and the related bending emissions in single microwires shows the possibility to fabricate special-shaped light sources and offer a method to develop photoelectronic devices.
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Affiliation(s)
- Linlin Shi
- State Key Laboratory of High Power Semiconductor Laser, Changchun University of Science and Technology, No. 7186 Wei-Xing Road, Changchun 130022, China; (H.W.); (X.M.)
| | - Hong Wang
- State Key Laboratory of High Power Semiconductor Laser, Changchun University of Science and Technology, No. 7186 Wei-Xing Road, Changchun 130022, China; (H.W.); (X.M.)
| | - Xiaohui Ma
- State Key Laboratory of High Power Semiconductor Laser, Changchun University of Science and Technology, No. 7186 Wei-Xing Road, Changchun 130022, China; (H.W.); (X.M.)
| | - Yunpeng Wang
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, No. 3888 Dongnanhu Road, Changchun 130033, China; (Y.W.); (F.W.); (D.Z.); (D.S.)
| | - Fei Wang
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, No. 3888 Dongnanhu Road, Changchun 130033, China; (Y.W.); (F.W.); (D.Z.); (D.S.)
| | - Dongxu Zhao
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, No. 3888 Dongnanhu Road, Changchun 130033, China; (Y.W.); (F.W.); (D.Z.); (D.S.)
| | - Dezhen Shen
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, No. 3888 Dongnanhu Road, Changchun 130033, China; (Y.W.); (F.W.); (D.Z.); (D.S.)
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