Well-integrated ZnO nanorod arrays on conductive textiles by electrochemical synthesis and their physical properties
- Yeong Hwan Ko1,
- Myung Sub Kim1,
- Wook Park1 and
- Jae Su Yu1Email author
https://doi.org/10.1186/1556-276X-8-28
© Ko et al.; licensee Springer. 2013
Received: 27 November 2012
Accepted: 4 January 2013
Published: 15 January 2013
Abstract
We reported well-integrated zinc oxide (ZnO) nanorod arrays (NRAs) on conductive textiles (CTs) and their structural and optical properties. The integrated ZnO NRAs were synthesized by cathodic electrochemical deposition on the ZnO seed layer-coated CT substrate in ultrasonic bath. The ZnO NRAs were regularly and densely grown as well as vertically aligned on the overall surface of CT substrate, in comparison with the grown ZnO NRAs without ZnO seed layer or ultrasonication. Additionally, their morphologies and sizes can be efficiently controlled by changing the external cathodic voltage between the ZnO seed-coated CT substrate and the counter electrode. At an external cathodic voltage of −2 V, the photoluminescence property of ZnO NRAs was optimized with good crystallinity and high density.
Keywords
Background
Vertically aligned one-dimensional (1D) zinc oxide (ZnO) nanostructures, such as nanorod and nanowire arrays, have attracted much interest in various application fields including field-emission devices, light-emitting diodes, piezoelectric devices, dye-sensitized solar cells, chemical sensors, and photodetectors due to their superior structural and optical properties compared to the bulk structure [1–7]. Over the past decade, there have been many efforts for controlling the structural and morphological properties of the 1D ZnO nanostructures with high density and uniformity because their size, shape, distribution, and crystallinity are closely related to the physical properties [8–10]. Furthermore, the hierarchical architectures built by the 1D ZnO nanostructures with 2D or 3D templates, which look like flowers or urchins, have potentially exhibited the improvements of device performance due to the highly extended surface area and density [11–14]. Nowadays, some vigorous attempts begin to be focused on the growth and deposition of the 1D ZnO nanostructures on various functional material substrates, for example, indium tin oxide-coated polyethylene terephthalate (i.e., ITO/PET) films, metal foils, graphenes, and cellulose fibers, thus leading to the merits of flexible and bendable feasibility with light weight and low cost [15–18].
On the other hand, the fabrication technique of conductive textiles (CTs) has been considerably developed by utilizing an electroless metallization of polymer fibers, and thus they have been used for electromagnetic interference shielding fabrics and flexible electrodes [19, 20]. In addition, the CTs can be a promising candidate as substrate for integrating the 1D ZnO nanostructures by employing the electrochemical deposition (ED) method. When electrons are supplied into the conductive surface in growth solution, ZnO nanorods can be readily synthesized and controlled at a low temperature by varying the external cathodic voltage [15, 21]. Therefore, the ED process with CT substrate can be a powerful and convenient fabrication method for preparing the vertically aligned 1D ZnO nanostructures on a conductive and flexible substrate. In this paper, we synthesized and controlled the integrated ZnO nanorod arrays (NRAs) on nickel (Ni)-coated PET fiber CTs by ED method with different external cathodic voltages. For more regular and dense ZnO NRAs, the CTs were coated by the ZnO seed solution, and the samples were treated by ultrasonic agitation during ED process.
Methods
All chemicals were purchased from Sigma-Aldrich (St. Louis, MO, USA), which were of analytical grade. To synthesize the ZnO NRAs on CT substrates, we used the commercially available CT substrates which consisted of woven Ni-plated PET (i.e., Ni/PET) fibers. For preparing the working substrate, the CT substrate of 3 × 3 cm2 was cleaned by ethanol and deionized (DI) water in ultrasonic bath for 10 min, respectively, at room temperature. The seed solution was made by dissolving the 10 mM of zinc acetate dehydrate (Zn(CH3COO)2 2H2O) in 50 ml of ethanol and by adding 1.5 wt.% of sodium dodecyl sulfate solution (CH3(CH2)11OSO3Na). After that, the CF substrates were dipped into the seed solution and pulled up slowly. To achieve good adhesion between the coated seed layer and the surface of CT, the samples were placed in the oven at 130°C for 2 h. Meanwhile, the aqueous growth solution was prepared by dissolving the 10 mM of zinc nitrate hexahydrate (Zn(NO3)2 6H2O) and 10 mM of hexamethylenetetramine ((CH2)6 N4) in 900 ml of DI water at 74 to 76°C under magnetic stirring. For growing the ZnO NRAs via the ED process, we used a simple two-electrode system containing the working electrode (i.e., deposited sample) and counter electrode (i.e., platinum mesh) since it is convenient and cost-effective for the synthesis of metal oxides nanostructures [22, 23]. For providing reliable information on the growth condition in ED process, the time-dependent applied current densities were recorded at different external cathodic voltages. In order to investigate the effect of external cathodic voltage on the growth property of ZnO NRAs, the samples were fabricated at various cathodic voltages from −1.6 to −2.8 V for 1 h. Herein, the pH value of growth solution was measured in the range of approximately 6.25 to 6.5 during the ED process. The morphologies and structural properties were observed by using a field-emission scanning electron microscope (FE-SEM; LEO SUPRA 55, Carl Zeiss, Reutlingen, Germany) and a transmission electron microscope (TEM; JEM 200CX, JEOL, Tokyo, Japan). The crystallinity and optical property were analyzed by the X-ray diffraction (XRD; M18XHF-SRA, Mac Science Ltd., Yokohama, Japan) patterns and the photoluminescence (PL; RPM2000, Accent Optical Technologies, York, UK) spectra, respectively.
Results and discussion
Schematic diagram. ED process for the ZnO NRAs on CT substrates. (a) The preparation of CT substrate, (b) the ZnO seed-coated CT substrate, and (c) the integrated ZnO NRAs on the seed-coated CT substrate.
FE-SEM micrographs. Integrated ZnO NRAs on the seed-coated CT substrate at an external cathodic voltage of −2 V for 1 h under ultrasonic agitation. (a) Low magnification, (b) medium magnification, and (c) high magnification. The insets of (c) show the magnified FE-SEM image of the selected region and the photographs of the bare CT and the ZnO NRAs integrated CT substrate.
FE-SEM micrographs. ZnO NRAs grown on (a), the bare CT substrate with the ultrasonic agitation; and (b), the seed-coated CT substrate without the ultrasonic agitation. For comparison, the external cathodic voltage and growth time were −2 V and 1 h, respectively, as the same condition of Figure 2.
FE-SEM micrographs and applied current densities. Synthesized ZnO on the seed-coated CT substrate at different external cathodic voltages of (a) −1.6 V, (b) −2.4 V, and (c) −2.8 V for 1 h under ultrasonic agitation, and (d) current density as a function of growth time at different external cathodic voltages. The insets of (a to c) show the magnified SEM images of the selected region of the corresponding samples.
XRD patterns and TEM images. (a) Synthesized ZnO on the seed-coated CT substrate at different external cathodic voltages from −1.6 to −2.8 V for 1 h under ultrasonic agitation, and (b) TEM image (left) and SAED pattern (right) of the single nanorod detached from the ZnO NRAs grown at −2 V. For comparison, the XRD pattern of bare CT substrate is also given in (a). The inset of (b) shows the HR TEM image of the ZnO nanorod.
Room-temperature PL spectra. Bare CT substrate and the synthesized ZnO on the seed-coated CT substrate at different external cathodic voltages from −1.6 to −2.8 V for 1 h under ultrasonic agitation. The inset shows the PL peak intensity and FWHM of the synthesized ZnO as a function of external cathodic voltage.
Conclusions
The ZnO NRAs were successfully integrated on the CT substrate (i.e., woven by Ni/PET fibers) by the ED process using the seed layer and ultrasonic agitation under a proper external cathodic voltage of −2 V for 1 h. The sizes/heights of ZnO NRAs were distributed to be approximately 65 to 80 nm/600 to 800 nm, and they could be clearly coated over the whole surface of the CT substrate with the seed layer and ultrasonic agitation. In a comparative investigation, it is clearly observed that the seed layer and ultrasonic agitation played key roles in providing a uniform organization of the ZnO NRAs with good nuclei sites as well as removing the adhesive ZnO microrods. Additionally, the well-integrated ZnO NRAs exhibited a narrow and strong PL NBE emission with good crystallinity. This optimal ED process for the well-integrated ZnO NRAs on CT substrates can be an essential growth technique for producing flexible and wearable functional materials in ZnO-based optoelectronic and electrochemical devices.
Declarations
Acknowledgments
This research was supported by the basic science research program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (no. 2011-0026393).
Authors’ Affiliations
References
- Li C, Fang G, Liu N, Li J, Liao L, Su F, Li G, Wu X, Zhao X: Structural, photoluminescence, and field emission properties of vertically well-aligned ZnO nanorod arrays. J Phys Chem C 2007, 111: 12566. 10.1021/jp0737808View ArticleGoogle Scholar
- Lai E, Kim W, Yang P: Vertical nanowire array-based light emitting diodes. Nano Res 2008, 1: 123. 10.1007/s12274-008-8017-4View ArticleGoogle Scholar
- Wang ZL, Song J: Piezoelectric nanogenerators based on zinc oxide nanowire arrays. Science 2006, 312: 242. 10.1126/science.1124005View ArticleGoogle Scholar
- Xu S, Qin Y, Xu C, Wei Y, Yang R, Wang ZL: Self-powered nanowire devices. Nat Nanotech 2010, 5: 366. 10.1038/nnano.2010.46View ArticleGoogle Scholar
- Zhang Q, Dandeneau CS, Zhou X, Cao G: ZnO nanostructures for dye-sensitized solar cells. Adv Mater 2009, 21: 4087. 10.1002/adma.200803827View ArticleGoogle Scholar
- Park JY, Song DE, Kim SS: An approach to fabricating chemical sensors based on ZnO nanorod arrays. Nanotechnol 2008, 19: 105503. 10.1088/0957-4484/19/10/105503View ArticleGoogle Scholar
- Lu CY, Chang SJ, Chang SP, Lee CT, Kuo CF, Chang HM: Ultraviolet photodetectors with ZnO nanowires prepared on ZnO:Ga/glass templates. Appl Phys Lett 2006, 89: 153101. 10.1063/1.2360219View ArticleGoogle Scholar
- Wang ZL: Zinc oxide nanostructures: growth, properties and applications. J Phys Condens Matter 2004, 16: R829. 10.1088/0953-8984/16/25/R01View ArticleGoogle Scholar
- Djurišić AB, Leung YH: Optical properties of ZnO nanostructures. Small 2006, 2: 944. 10.1002/smll.200600134View ArticleGoogle Scholar
- Baruah S, Dutta J: Hydrothermal growth of ZnO nanostructures. Sci Techno. Adv Mater 2009, 10: 013001. 10.1088/1468-6996/10/1/013001View ArticleGoogle Scholar
- Shen G, Bando Y, Lee CJ: Synthesis and evolution of novel hollow ZnO urchins by a simple thermal evaporation process. J Phys Chem B 2008, 109: 10578.View ArticleGoogle Scholar
- Lao JY, Wen JG, Ren ZF: Hierarchical ZnO nanostructures. Nano Lett 2002, 2: 1287. 10.1021/nl025753tView ArticleGoogle Scholar
- Ko YH, Yu JS: Tunable growth of urchin-shaped ZnO nanostructures on patterned transparent substrates. Cryst Eng Comm 2012, 14: 5824. 10.1039/c2ce25284hView ArticleGoogle Scholar
- Elias J, Clément CL, Bechelany M, Michler J, Wang GY, Wang Z, Philipp L: Hollow urchin-like ZnO thin films by electrochemical deposition. Adv Mater 2012, 22: 1607.View ArticleGoogle Scholar
- Ko YH, Kim MS, Yu JS: Controllable electrochemical synthesis of ZnO nanorod arrays on flexible ITO/PET substrate and their structural and optical properties. App. Surf Sci 2012, 259: 99.View ArticleGoogle Scholar
- Umar A, Kim BK, Kim JJ, Hahn YB: Optical and electrical properties of ZnO nanowires grown on aluminium foil by non-catalytic thermal evaporation. Nanotechnol 2007, 18: 17566.View ArticleGoogle Scholar
- Akhavan O: Graphene nanomesh by ZnO nanorod photocatalysts. ACS Nano 2010, 4: 4174. 10.1021/nn1007429View ArticleGoogle Scholar
- Gullapalli H, Vemuru VSM, Kumar A, Mendez AB, Vajtai R, Terrones M, Nagarajaiah S, Ajayan PM: Flexible piezoelectric ZnO-paper nanocomposite strain sensor. Small 2010, 6: 1641. 10.1002/smll.201000254View ArticleGoogle Scholar
- Perumalraj R, Dasaradan BS: Electroless nickel plated composite materials for electromagnet compatibility. Indian J Fibre Text Res 2011, 36: 35.Google Scholar
- Anderson EB, Ingildeev D, Hermanutz F, Muller A, Schweizer M, Buchmeiser MR: Synthesis and dry-spinning fibers of sulfinyl-based poly(p-phenylene vinylene) (PPV) for semi-conductive textile applications. J Mater Chem 2012, 22: 11851. 10.1039/c2jm30186eView ArticleGoogle Scholar
- Lee HK, Kim MS, Yu JS: Effect of AZO seed layer on electrochemical growth and optical properties of ZnO nanorod arrays on ITO glass. Nanotechnol 2011, 22: 445602. 10.1088/0957-4484/22/44/445602View ArticleGoogle Scholar
- Singh DP, Singh J, Mishra PR, Tiwari RS, Srivastava ON: Synthesis, characterization and application of semiconducting oxide (Cu2O and ZnO) nanostructures. Bull Mater Sci 2008, 31: 319. 10.1007/s12034-008-0051-zView ArticleGoogle Scholar
- Hassan NK, Hashim MR, Douri YA, Heuseen KA: Current dependence growth of ZnO nanostructures by electrochemical deposition technique. Int J Electrochem Sci 2012, 7: 4625.Google Scholar
- Postels B, Bakin A, Wehmann HH, Suleiman M, Weimann T, Hinze P, Waag A: Electrodeposition of ZnO nanorods for device application. Appl Phys A 2008, 91: 595. 10.1007/s00339-008-4487-1View ArticleGoogle Scholar
- Ko YH, Yu JS: Structural and antireflective properties of ZnO nanorods synthesized using the sputtered ZnO seed layer for solar cell applications. J Nanosci Nanotechnol 2010, 10: 8095. 10.1166/jnn.2010.3020View ArticleGoogle Scholar
- Lee YJ, Ruby DS, Peters DW, McKenzie BB, Hsu JWPL: ZnO nanostructures as efficient antireflection layers in solar cells. Nano Lett 2008, 8: 1501. 10.1021/nl080659jView ArticleGoogle Scholar
- Baek SH, Noh BY, Park IK, Kim JH: Fabrication and characterization of silicon wire solar cells having ZnO nanorod antireflection coating on Al-doped ZnO seed layer. Nanoscale Res Lett 2012, 7: 29. 10.1186/1556-276X-7-29View ArticleGoogle Scholar
- Pauporté T, Bataille G, Joulaud L, Vermersch FJ: Well-aligned ZnO nanowire arrays prepared by seed-layer-free electrodeposition and their Cassie-Wenzel transition after hydrophobization. J Phys Chem C 2010, 114: 194. 10.1021/jp9087145View ArticleGoogle Scholar
- Suleiman MA, Mofor AC, Shaer AE, Bakin A, Wehmann HH, Waag A: Photoluminescence properties: catalyst-free ZnO nanorods and layers versus bulk ZnO. Appl Phys Lett 89: 231911.Google Scholar
- Sugunan A, Warad HC, Boman M, Dutta J: Zinc oxide nanowires in chemical bath on seeded substrates: role of hexamine. J Sol-Gel Sci Technol 2006, 39: 49. 10.1007/s10971-006-6969-yView ArticleGoogle Scholar
- Yang CJ, Wang SM, Liang SW, Chang YH, Chen C, Shieh JM: Low-temperature growth of ZnO nanorods in anodic aluminum oxide on Si substrate by atomic layer deposition. Appl Phys Lett 2007, 90: 033104. 10.1063/1.2431786View ArticleGoogle Scholar
- Beverskog B, Puigdomenech I: Revised Pourbaix diagrams for zinc at 25–300°C. Corros Sci 1997, 39: 107. 10.1016/S0010-938X(97)89246-3View ArticleGoogle Scholar
Copyright
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.