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Thermal nanoimprint lithography based plasmonic nanogratings for refractive index sensing of polar solvents
Materials Today: Proceedings xxx (xxxx) xxx
Contents lists available at ScienceDirect
Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr
Thermal nanoimprint lithography based plasmonic nanogratings for refractive index sensing of polar solvents Saswat Mohapatra, Udit Pant, Rakesh S. Moirangthem ⇑ Nanophotonics Lab, Department of Physics, Indian Institute of Technology (Indian School of Mines), Dhanbad 826004, India
a r t i c l e
i n f o
Article history: Received 25 January 2020 Accepted 30 January 2020 Available online xxxx Keywords: Thermal nanoimprint lithography (T-NIL) surface plasmon resonance (SPR) Nanogratings Plasmonic sensor Polar solvents
a b s t r a c t This work illustrates a facile approach for the design of flexible plasmonic sensors using gold nanograting. The fabrication of surface plasmon resonance (SPR) coupled refractive index (RI) sensor is proposed to sense the various known RIs of polar solvents. Thermal nanoimprint lithography (T-NIL) is used to transfer the nanograting of the processed digital versatile discs (DVDs) through polydimethylsiloxane (PDMS) stamp to thermoplastic polymer coated flexible polyethylene terephthalate (PET) substrate. The gold nanograting sample was obtained after the subsequent deposition of the gold thin film of thickness 60 nm on top of polymer nanograting. The surface plasmon resonance (SPR) modes excited on goldencrusted polymer nanograting appeared as a dip in the reflectance spectra measured at normal incidence under white light in air and liquid medium. We use refractive index calibration polar solvents [methanol (1.331), water (1.333), acetone (1.359), ethanol (1.361) and isopropanol (1.382)] to determine the refractive index sensitivity of our gold nanograting arrays. This produces a bulk refractive index sensitivity of 535 ± 47 nm/RIU. The real-time kinetic response demonstrates the stability of the sensor with respect to the time and reusability of the sensing chip for multiple measurements. Thus, we envisaged that our proposed sensor can be a potential candidate for the development of highly sensitive plamonic device. Ó 2020 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility of the scientific committee of the International Conference on Advanced Materials and Nanotechnology.
1. Introduction Fabricated metal nanostructures used in plasmonic sensors have unique optical properties. Various types of lithographic technique, such as electron beam lithography (EBL), nanosphere lithography (NSL), and focused ion beam lithography (FIBL) etc., have been used for fabrication of different shape and sizes of the metal nanostructures [1–5]. By varying the parameters of nanostructures like size, shape and spacing between consecutive nanostructures the surface plasmon resonance (SPR) mode can be calibrated and hence sensitivity can be enhanced. However, this high-cost and time taking fabrication process creates difficulties in further commercialization. As a solution to these difficulties, soft nanoimprint lithography is used as a facile technique to prepare plasmonic nanostructures on a large scale [6–8]. Thermal nanoimprint lithography (T-NIL) is a type of soft lithography technique that uses flexible polydimethylsiloxane (PDMS) stamp to imprint the ⇑ Corresponding author.
nanostructures from master template to desired thermoplastic polymer coated substrate. Further, to reduce the cost of the master templates several research groups have used the metal coated nanograting of optical disc as a master template [9–16]. In this manuscript, a facile T-NIL technique is presented in which we have used an ideal thermoplastic materials available in the stationary shop at a very reasonable price. Here the polymeric solutions was prepared in chloroform and spin-coated over the flexible polyethylene terephthalate (PET) substrate. Further, the nanograting was imprinted on the top of the thermoplastic polymer coated PET substrate by using a custom made T-NIL setup, followed by desired gold deposition to prepare the plasmonic sensor chip [13,17]. At the time of measurements, the reflection spectra shows the SPR mode around 761 nm in ambient air medium. Afterwards, we used different refractive indices of known solutions to determine the refractive index sensitivity of our gold nanograting array. These refractive index sensitivity indicate that the thermoplastic polymeric materials is a promising candidate for fabrication of various plasmonic sensors in future.
E-mail address: [email protected] (R.S. Moirangthem). https://doi.org/10.1016/j.matpr.2020.01.581 2214-7853/Ó 2020 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility of the scientific committee of the International Conference on Advanced Materials and Nanotechnology.
Please cite this article as: S. Mohapatra, U. Pant and R. S. Moirangthem, Thermal nanoimprint lithography based plasmonic nanogratings for refractive index sensing of polar solvents, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2020.01.581
2
S. Mohapatra et al. / Materials Today: Proceedings xxx (xxxx) xxx
2. Experimental procedure The whole experimental part consists of three parts, fabrication of nanograting using T-NIL, structural characterization and optical measurements. Fig. 1(a) shows the complete flow chart of fabrication using T-NIL. The inset image shows the imprinted sample using T-NIL. Using T-NIL setup the nanograting sample was obtained followed by 60 nm of gold on top of polymer nanograting. Fig. 1 (b) is a picture of complete optical setup for reflectance measurements with inset image shows the flow cell attached with nanograting sample. Fig. 1 (c) presents the FESEM image of 60 nm gold encrusted polymer nanograting. From the FESEM image the line width and periodicity of the nanograting are found to be 542 nm and 731 nm respectively. Fig. 1 (d) shows the height profile of AFM image and the height profile of nanograting was found to be 90 nm. Further we fixed the gold nanograting on the flow cell to measure the SPR response with respect to the change in ambient medium. The SPR modes excited on gold encrusted polymer nanograting appeared as a dip in the reflectance spectra measured at normal incidence under white light in air and liquid medium. Various solutions [methanol (1.331), water (1.333), acetone (1.359), ethanol (1.361) and isopropanol (1.382)] were used to determine the refractive index sensitivity.
3. Results analysis In refractive index sensing, initially the reflectance spectrum was recorded in air and then for other polar solvents. Due to change in surrounding medium from air to methanol solvents, the SPR mode observed in air medium was red-shifted from 761 nm to 973 nm. Fig. 2(a) shows the reflectance spectra in the ambient air medium. In the similar way, the successive passage of polar solvents [methanol (1.331), water (1.333), acetone (1.359), ethanol (1.361) and isopropanol (1.382)] over the SPR sensor, a clear shifting of SPR dip between 972 nm and 1002 nm can be observed as a result of increasing refractive indices. The corresponding reflectance spectra with respect to various polar solvents
are shown in Fig. 2(b). The shifting of SPR dip with increasing in refractive indices shows a linear relation, and a linear fitting of the SPR dip wavelengths gives a slope in the form of bulk sensitivity of 535 ± 47 nm/RIU (refractive index unit). Fig. 2(c) shows the linear fitting of SPR dip and bulk sensitivity. The error bar shown in the plot was obtained from the repetition of the measurements from three different spots on the same sample to confirm the uniformity of the nanograting over a larger area. Furthermore, a real time kinetic measurements was taken at 974 nm with respect to the change in surrounding medium of various refractive indices as depicted in Fig. 2(d). From this graph, it is clearly observed that the response gradually increases in steps with increase in RIs with respect to time and returns its original wavelength value when the same solution (methanol) flows over the sensing surface. This indicates the reusability of the sample for multiple measurements. 4. Conclusion In this article, we have reported the nanograting fabrication, morphological characterization and optical measurements of plasmonic refractive index sensor on a flexible substrate using T-NIL. The real-time sensing properties were tested for detecting the refractive indices of polar solvents. From the experiment, the bulk refractive index sensitivity was obtained as 535 ± 47 nm/RIU. The real time kinetics graph shows quite stable steps in the sensor surface while flowing various analytes and returns its original position while flowing the initial solvents over the sensor surface. Hence, the sensing chip can be reusable for multiple experiments. Our proposed sensor is simple to design and fabricated with low-cost which can make it a potential candidate for chemical and biological sensing. Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Fig. 1. (a) Different steps of the T-NIL involved in the sample fabrication (inset shows imprinted sample), (b) photograph of reflectance measurement setup, (c) and (d) FESEM and AFM images of gold coated sample (inset of (d) shows the height profile of gold grating (90 nm)).
Please cite this article as: S. Mohapatra, U. Pant and R. S. Moirangthem, Thermal nanoimprint lithography based plasmonic nanogratings for refractive index sensing of polar solvents, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2020.01.581
S. Mohapatra et al. / Materials Today: Proceedings xxx (xxxx) xxx
3
Fig. 2. (a) Reflectance spectrum in air medium, (b) reflectance spectra of various polar solvents, (c) Reflectance dip shift of wavelength with respect to refractive index (error bars for repeated experiment) and (d) real time kinetic response of the sensor.
Acknowledgement Authors are thankful to Indian Institute of Technology (Indian School of Mines), Dhanbad for providing the research facilities. This work is financially supported by the Science and Engineering Research Board (SERB), under grant number: EEQ/2017/000370. References [1] A.E. Cetin, S.N. Topkaya, Photonic crystal and plasmonic nanohole based labelfree biodetection, Biosens. Bioelectron. 132 (2019) 196–202. [2] M. Altissimo, E-beam lithography for micro-/nanofabrication, Biomicrofluidics 4 (2) (2010) 026503. [3] K. Bi, Y. Chen, Q. Wan, T. Ye, Q. Xiang, M. Zheng, X. Wang, et al., Direct electronbeam patterning of transferrable plasmonic gold nanoparticles using a HAuCl 4/PVP composite resist, Nanoscale 11 (3) (2019) 1245–1252. [4] C. Chou, Y. Fong, K.H. Chen, H.P. Chiang, C.M. Lim, H.J. Huang, C.H. Lai, N.T.R.N. Kumara, Fabrication and Characterization of a Metallic-Dielectric Nanorod Array by Nanosphere Lithography for Plasmonic Sensing Application, Nanomaterials 9 (12) (2019) 1691. [5] S. Kasani, K. Curtin, N. Wu, A review of 2D and 3D plasmonic nanostructure array patterns: fabrication, light management and sensing applications, Nanophotonics 8 (12) (2019) 2065–2089. [6] S.W. Lee, K.S. Lee, J. Ahn, J.J. Lee, M.G. Kim, Y.B. Shin, Highly sensitive biosensing using arrays of plasmonic Au nanodisks realized by nanoimprint lithography, ACS Nano 5 (2) (2011) 897–904. [7] C. Probst, C. Meichner, K. Kreger, L. Kador, C. Neuber, H.W. Schmidt, Athermal Azobenzene-Based Nanoimprint Lithography, Adv. Mater. 28 (13) (2016) 2624–2628.
[8] S. Mohapatra, S. Kumari, R.S. Moirangthem, Fabrication of a cost-effective polymer nanograting as a disposable plasmonic biosensor using nanoimprint lithography, Mater. Res. Express 4 (7) (2017) 076202. [9] C. Leordean, A.M. Gabudean, V. Canpean, S. Astilean, Easy and cheap fabrication of ordered pyramidal-shaped plasmonic substrates for detection and quantitative analysis using surface-enhanced Raman spectroscopy, Analyst 138 (2013) 4975–4981. [10] Y. Sun, S. Sun, M. Wu, S. Gao, J. Cao, Refractive index sensing using the metal layer in DVD-R discs, RSC Adv. 8 (2018) 27423–27428. [11] B. Kaplan, H. Guner, O. Senlik, K. Gurel, M. Bayindir, A. Dana, Tuning optical discs for plasmonic applications, Plasmonics 4 (2009) 237–243. [12] X. Dou, P.Y. Chung, P. Jiang, J. Dai, Surface plasmon resonance and surfaceenhanced Raman scattering sensing enabled by digital versatile discs, Appl. Phys. Lett. 100 (2012) 041116. [13] K. Gurel, B. Kaplan, H. Guner, M. Bayindir, A. Dana, Resonant transmission of light through surface plasmon structures, Appl. Phys. Lett. 94 (2009) 233102. [14] X. Dou, B.M. Phillips, P.Y. Chung, P. Jiang, High surface plasmon resonance sensitivity enabled by optical disks, Opt. Lett. 37 (2012) 3681–3683. [15] B.K. Singh, A.C. Hillier, Surface plasmon resonance imaging of biomolecular interactions on a grating-based sensor array, Anal. Chem. 78 (2006) 2009– 2018. [16] S. Mohapatra, and R. S. Moirangthem. ‘‘Study of sequential nanoimprint lithography using optical disc on polymer coated plastic substrate.” In 2018 3rd International Conference on Microwave and Photonics (ICMAP), pp. 1-2. IEEE, 2018. [17] S. Mohapatra, R.S. Moirangthem, Fabrication of flexible and economical plasmonic biosensor using gold nanograting imprinted on hot-melt adhesive film for label-free sensing of immunoglobulin proteins, Sens. Actuators B 301 (2019) 127070.
Please cite this article as: S. Mohapatra, U. Pant and R. S. Moirangthem, Thermal nanoimprint lithography based plasmonic nanogratings for refractive index sensing of polar solvents, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2020.01.581
Contents lists available at ScienceDirect
Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr
Thermal nanoimprint lithography based plasmonic nanogratings for refractive index sensing of polar solvents Saswat Mohapatra, Udit Pant, Rakesh S. Moirangthem ⇑ Nanophotonics Lab, Department of Physics, Indian Institute of Technology (Indian School of Mines), Dhanbad 826004, India
a r t i c l e
i n f o
Article history: Received 25 January 2020 Accepted 30 January 2020 Available online xxxx Keywords: Thermal nanoimprint lithography (T-NIL) surface plasmon resonance (SPR) Nanogratings Plasmonic sensor Polar solvents
a b s t r a c t This work illustrates a facile approach for the design of flexible plasmonic sensors using gold nanograting. The fabrication of surface plasmon resonance (SPR) coupled refractive index (RI) sensor is proposed to sense the various known RIs of polar solvents. Thermal nanoimprint lithography (T-NIL) is used to transfer the nanograting of the processed digital versatile discs (DVDs) through polydimethylsiloxane (PDMS) stamp to thermoplastic polymer coated flexible polyethylene terephthalate (PET) substrate. The gold nanograting sample was obtained after the subsequent deposition of the gold thin film of thickness 60 nm on top of polymer nanograting. The surface plasmon resonance (SPR) modes excited on goldencrusted polymer nanograting appeared as a dip in the reflectance spectra measured at normal incidence under white light in air and liquid medium. We use refractive index calibration polar solvents [methanol (1.331), water (1.333), acetone (1.359), ethanol (1.361) and isopropanol (1.382)] to determine the refractive index sensitivity of our gold nanograting arrays. This produces a bulk refractive index sensitivity of 535 ± 47 nm/RIU. The real-time kinetic response demonstrates the stability of the sensor with respect to the time and reusability of the sensing chip for multiple measurements. Thus, we envisaged that our proposed sensor can be a potential candidate for the development of highly sensitive plamonic device. Ó 2020 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility of the scientific committee of the International Conference on Advanced Materials and Nanotechnology.
1. Introduction Fabricated metal nanostructures used in plasmonic sensors have unique optical properties. Various types of lithographic technique, such as electron beam lithography (EBL), nanosphere lithography (NSL), and focused ion beam lithography (FIBL) etc., have been used for fabrication of different shape and sizes of the metal nanostructures [1–5]. By varying the parameters of nanostructures like size, shape and spacing between consecutive nanostructures the surface plasmon resonance (SPR) mode can be calibrated and hence sensitivity can be enhanced. However, this high-cost and time taking fabrication process creates difficulties in further commercialization. As a solution to these difficulties, soft nanoimprint lithography is used as a facile technique to prepare plasmonic nanostructures on a large scale [6–8]. Thermal nanoimprint lithography (T-NIL) is a type of soft lithography technique that uses flexible polydimethylsiloxane (PDMS) stamp to imprint the ⇑ Corresponding author.
nanostructures from master template to desired thermoplastic polymer coated substrate. Further, to reduce the cost of the master templates several research groups have used the metal coated nanograting of optical disc as a master template [9–16]. In this manuscript, a facile T-NIL technique is presented in which we have used an ideal thermoplastic materials available in the stationary shop at a very reasonable price. Here the polymeric solutions was prepared in chloroform and spin-coated over the flexible polyethylene terephthalate (PET) substrate. Further, the nanograting was imprinted on the top of the thermoplastic polymer coated PET substrate by using a custom made T-NIL setup, followed by desired gold deposition to prepare the plasmonic sensor chip [13,17]. At the time of measurements, the reflection spectra shows the SPR mode around 761 nm in ambient air medium. Afterwards, we used different refractive indices of known solutions to determine the refractive index sensitivity of our gold nanograting array. These refractive index sensitivity indicate that the thermoplastic polymeric materials is a promising candidate for fabrication of various plasmonic sensors in future.
E-mail address: [email protected] (R.S. Moirangthem). https://doi.org/10.1016/j.matpr.2020.01.581 2214-7853/Ó 2020 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility of the scientific committee of the International Conference on Advanced Materials and Nanotechnology.
Please cite this article as: S. Mohapatra, U. Pant and R. S. Moirangthem, Thermal nanoimprint lithography based plasmonic nanogratings for refractive index sensing of polar solvents, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2020.01.581
2
S. Mohapatra et al. / Materials Today: Proceedings xxx (xxxx) xxx
2. Experimental procedure The whole experimental part consists of three parts, fabrication of nanograting using T-NIL, structural characterization and optical measurements. Fig. 1(a) shows the complete flow chart of fabrication using T-NIL. The inset image shows the imprinted sample using T-NIL. Using T-NIL setup the nanograting sample was obtained followed by 60 nm of gold on top of polymer nanograting. Fig. 1 (b) is a picture of complete optical setup for reflectance measurements with inset image shows the flow cell attached with nanograting sample. Fig. 1 (c) presents the FESEM image of 60 nm gold encrusted polymer nanograting. From the FESEM image the line width and periodicity of the nanograting are found to be 542 nm and 731 nm respectively. Fig. 1 (d) shows the height profile of AFM image and the height profile of nanograting was found to be 90 nm. Further we fixed the gold nanograting on the flow cell to measure the SPR response with respect to the change in ambient medium. The SPR modes excited on gold encrusted polymer nanograting appeared as a dip in the reflectance spectra measured at normal incidence under white light in air and liquid medium. Various solutions [methanol (1.331), water (1.333), acetone (1.359), ethanol (1.361) and isopropanol (1.382)] were used to determine the refractive index sensitivity.
3. Results analysis In refractive index sensing, initially the reflectance spectrum was recorded in air and then for other polar solvents. Due to change in surrounding medium from air to methanol solvents, the SPR mode observed in air medium was red-shifted from 761 nm to 973 nm. Fig. 2(a) shows the reflectance spectra in the ambient air medium. In the similar way, the successive passage of polar solvents [methanol (1.331), water (1.333), acetone (1.359), ethanol (1.361) and isopropanol (1.382)] over the SPR sensor, a clear shifting of SPR dip between 972 nm and 1002 nm can be observed as a result of increasing refractive indices. The corresponding reflectance spectra with respect to various polar solvents
are shown in Fig. 2(b). The shifting of SPR dip with increasing in refractive indices shows a linear relation, and a linear fitting of the SPR dip wavelengths gives a slope in the form of bulk sensitivity of 535 ± 47 nm/RIU (refractive index unit). Fig. 2(c) shows the linear fitting of SPR dip and bulk sensitivity. The error bar shown in the plot was obtained from the repetition of the measurements from three different spots on the same sample to confirm the uniformity of the nanograting over a larger area. Furthermore, a real time kinetic measurements was taken at 974 nm with respect to the change in surrounding medium of various refractive indices as depicted in Fig. 2(d). From this graph, it is clearly observed that the response gradually increases in steps with increase in RIs with respect to time and returns its original wavelength value when the same solution (methanol) flows over the sensing surface. This indicates the reusability of the sample for multiple measurements. 4. Conclusion In this article, we have reported the nanograting fabrication, morphological characterization and optical measurements of plasmonic refractive index sensor on a flexible substrate using T-NIL. The real-time sensing properties were tested for detecting the refractive indices of polar solvents. From the experiment, the bulk refractive index sensitivity was obtained as 535 ± 47 nm/RIU. The real time kinetics graph shows quite stable steps in the sensor surface while flowing various analytes and returns its original position while flowing the initial solvents over the sensor surface. Hence, the sensing chip can be reusable for multiple experiments. Our proposed sensor is simple to design and fabricated with low-cost which can make it a potential candidate for chemical and biological sensing. Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Fig. 1. (a) Different steps of the T-NIL involved in the sample fabrication (inset shows imprinted sample), (b) photograph of reflectance measurement setup, (c) and (d) FESEM and AFM images of gold coated sample (inset of (d) shows the height profile of gold grating (90 nm)).
Please cite this article as: S. Mohapatra, U. Pant and R. S. Moirangthem, Thermal nanoimprint lithography based plasmonic nanogratings for refractive index sensing of polar solvents, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2020.01.581
S. Mohapatra et al. / Materials Today: Proceedings xxx (xxxx) xxx
3
Fig. 2. (a) Reflectance spectrum in air medium, (b) reflectance spectra of various polar solvents, (c) Reflectance dip shift of wavelength with respect to refractive index (error bars for repeated experiment) and (d) real time kinetic response of the sensor.
Acknowledgement Authors are thankful to Indian Institute of Technology (Indian School of Mines), Dhanbad for providing the research facilities. This work is financially supported by the Science and Engineering Research Board (SERB), under grant number: EEQ/2017/000370. References [1] A.E. Cetin, S.N. Topkaya, Photonic crystal and plasmonic nanohole based labelfree biodetection, Biosens. Bioelectron. 132 (2019) 196–202. [2] M. Altissimo, E-beam lithography for micro-/nanofabrication, Biomicrofluidics 4 (2) (2010) 026503. [3] K. Bi, Y. Chen, Q. Wan, T. Ye, Q. Xiang, M. Zheng, X. Wang, et al., Direct electronbeam patterning of transferrable plasmonic gold nanoparticles using a HAuCl 4/PVP composite resist, Nanoscale 11 (3) (2019) 1245–1252. [4] C. Chou, Y. Fong, K.H. Chen, H.P. Chiang, C.M. Lim, H.J. Huang, C.H. Lai, N.T.R.N. Kumara, Fabrication and Characterization of a Metallic-Dielectric Nanorod Array by Nanosphere Lithography for Plasmonic Sensing Application, Nanomaterials 9 (12) (2019) 1691. [5] S. Kasani, K. Curtin, N. Wu, A review of 2D and 3D plasmonic nanostructure array patterns: fabrication, light management and sensing applications, Nanophotonics 8 (12) (2019) 2065–2089. [6] S.W. Lee, K.S. Lee, J. Ahn, J.J. Lee, M.G. Kim, Y.B. Shin, Highly sensitive biosensing using arrays of plasmonic Au nanodisks realized by nanoimprint lithography, ACS Nano 5 (2) (2011) 897–904. [7] C. Probst, C. Meichner, K. Kreger, L. Kador, C. Neuber, H.W. Schmidt, Athermal Azobenzene-Based Nanoimprint Lithography, Adv. Mater. 28 (13) (2016) 2624–2628.
[8] S. Mohapatra, S. Kumari, R.S. Moirangthem, Fabrication of a cost-effective polymer nanograting as a disposable plasmonic biosensor using nanoimprint lithography, Mater. Res. Express 4 (7) (2017) 076202. [9] C. Leordean, A.M. Gabudean, V. Canpean, S. Astilean, Easy and cheap fabrication of ordered pyramidal-shaped plasmonic substrates for detection and quantitative analysis using surface-enhanced Raman spectroscopy, Analyst 138 (2013) 4975–4981. [10] Y. Sun, S. Sun, M. Wu, S. Gao, J. Cao, Refractive index sensing using the metal layer in DVD-R discs, RSC Adv. 8 (2018) 27423–27428. [11] B. Kaplan, H. Guner, O. Senlik, K. Gurel, M. Bayindir, A. Dana, Tuning optical discs for plasmonic applications, Plasmonics 4 (2009) 237–243. [12] X. Dou, P.Y. Chung, P. Jiang, J. Dai, Surface plasmon resonance and surfaceenhanced Raman scattering sensing enabled by digital versatile discs, Appl. Phys. Lett. 100 (2012) 041116. [13] K. Gurel, B. Kaplan, H. Guner, M. Bayindir, A. Dana, Resonant transmission of light through surface plasmon structures, Appl. Phys. Lett. 94 (2009) 233102. [14] X. Dou, B.M. Phillips, P.Y. Chung, P. Jiang, High surface plasmon resonance sensitivity enabled by optical disks, Opt. Lett. 37 (2012) 3681–3683. [15] B.K. Singh, A.C. Hillier, Surface plasmon resonance imaging of biomolecular interactions on a grating-based sensor array, Anal. Chem. 78 (2006) 2009– 2018. [16] S. Mohapatra, and R. S. Moirangthem. ‘‘Study of sequential nanoimprint lithography using optical disc on polymer coated plastic substrate.” In 2018 3rd International Conference on Microwave and Photonics (ICMAP), pp. 1-2. IEEE, 2018. [17] S. Mohapatra, R.S. Moirangthem, Fabrication of flexible and economical plasmonic biosensor using gold nanograting imprinted on hot-melt adhesive film for label-free sensing of immunoglobulin proteins, Sens. Actuators B 301 (2019) 127070.
Please cite this article as: S. Mohapatra, U. Pant and R. S. Moirangthem, Thermal nanoimprint lithography based plasmonic nanogratings for refractive index sensing of polar solvents, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2020.01.581