RGO Sheets

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C: Plasmonics; Optical, Magnetic, and Hybrid Materials

A Light Induced Tunable n-Doping of Ag Embedded GO/RGO Sheets in Polymer Matrix Neelam Singh, Deepak Kothari, Jamilur R Ansari, Mrinal Pal, Sankar Mandal, Sandip Dhara, and Anindya Datta J. Phys. Chem. C, Just Accepted Manuscript • DOI: 10.1021/acs.jpcc.9b01185 • Publication Date (Web): 13 Mar 2019 Downloaded from http://pubs.acs.org on March 14, 2019

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The Journal of Physical Chemistry

A Light Induced Tunable n-Doping of Ag Embedded GO/RGO Sheets in Polymer Matrix Neelam Singh1, Deepak Kothari1, Jamilur R. Ansari1, Mrinal Pal2, Sankar Mandal3, Sandip Dhara4 and Anindya Datta1,* 1 USBAS,

Guru Gobind Singh Indraprastha University Dwarka, New Delhi-110078, India

2 CSIR-Central

Glass & Ceramic Research Institute, Council of Scientific & Industrial Research,

Kolkata-700032, India 3Department 4Surface

of Physics, Barasat Govt. College Barasat, Kolkata-700124, India

and Nanoscience Science Division, Indira Gandhi Centre for Atomic Research, HBNI,

Kalpakkam- 603102, India

1 ACS Paragon Plus Environment

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ABSTRACT A series of composites were synthesized having graphene oxide (GO)/reduced graphene oxide (RGO), decorated with Ag halide within inert polyvinyl alcohol (PVA) matrix. A calculated amount of cuprous iodide was also synthesized with Ag halide. On exposure to light, due to the photochromic effect, Ag halide converts into Ag nanoparticles as a donor, whereas cuprous iodide acts as a hole trapper to introduce a band gap in graphene. With increasing exposure time, the Ag nanoparticles increase in size and number and composites become increasingly dark. The appearance of the plasmonic peak in ultra violet-visible plots after exposure to light confirms the presence of Ag nanoparticles in these composites. The apparent red-shift of the SPR peak, reduction of its intensity, and broadening of the peak are dependent on the dielectric constant of the surrounding matrix and the distance between the GO/RGO sheet and the Ag nanoparticles. The increasing number and size of Ag nanoparticles introduce tunable n-type doping in the GO/RGO-PVA composites, as determined directly by the Raman spectroscopy, without the necessity of electrically gated device.


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1. INTRODUCTION Monolayer graphene is an extraordinary material, being a zero band gap semiconductor1,2 as it constitutes the possibility of ultrafast electronics. However, for various kind of devices, the band gap is imperative, which can be achieved with multilayer graphene, or by the introduction of various types of functional groups and defects3–6. Changes in various kinds of electrical and optical properties of a graphene-based material can be achieved by doping. As a result of doping, a wide variety of applications are possible such as flexible electronics7,8 , field effect transistors9– 11,

energy storage as fuel cell and battery12,13, supercapacitors14–16, and electrochemical sensors17

to name a few. Various sources of doping are possible in graphene-related materials such as electrostatic, substitution, chemical, and optical doping and many of them can be studied well with Raman spectroscopy18. Impressive progress in the study of charge-transfer interactions of graphene with various electron donors and acceptors has been made19. In the chemical source of doping further classification can be made considering doping by boron and nitrogen20 and by molecular chargetransfer21. Local distortion or accidental doping sometimes give contrasting results in case of molecular charge transfer compared to electrostatic (gated) and chemical doping and needs further careful study. There are essentially two ways of doping graphene-based systems, namely, direct method of synthesis where the doping is introduced when the graphene is formed and post-treatment method, where doping is introduced at a later stage after graphene formation. The second method can be further subdivided as dry and wet method2.



Continuous charge carrier tuning from n-type to p-type doping is possible with very high magnitude of doping. At room temperature, the mobility of graphene can reach ∼120,000 cm2/Vs which are higher than any known semiconductor22,23. Doping will have a direct consequence in the development of graphene-based spintronics. The subject seems to be promising because of the observation of spin relaxation length of the order of ~2 m24,25. Observation of extremely high thermal conductivity (~3080-5150 W/mK) by Raman spectroscopy leads to the possibility of application in thermal management of future high-density nano-electronic chips, which obviously will be influenced by the various source of doping26. Most of these techniques introduce a fixed level of doping. In order to tune the doping level, it is necessary to have gated electrode structure27–31, which opens up the Dirac point to introduce bandgap tuning into the graphene structure and in turn creates controlled electrical and optical properties of graphene-based systems. Raman spectroscopy is widely used as a non-destructive tool for determining various aspects of graphene-related materials such as for studying the level of doping, finding accurately the number of layers, probing the chirality of graphene, and studying the strain related effects to name a few32–34. Our motivation in this work was whether one can create a graphene oxide/reduced graphene oxide (GO/RGO) based system, where the level of doping can be tuned without a gate electrode structure. Presence of noble metals like Ag and Au are known to introduce doping in graphenebased materials35. One of the best ways to study the level of doping non-electrically is to use Raman spectroscopy1. In a series of composites of Ag halide decorated GO/RGO, with PVA as a matrix, we have used the photochromic effect to create Ag nanoparticles. These Ag


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nanoparticles, decorating GO/RGO introduced tunable n-doping in the graphene-based backbone. The variable level of n-doping has been established with Raman spectroscopy in this work. 2. EXPERIMENT 2.1 Materials Graphite powder, potassium permanganate (KMNO4), sodium nitrate (NaNO3), hydrogen peroxide (H2O2) and sulfuric acid (H2SO4) was used for the synthesis of GO. Hydrazine hydrate was used to reduce GO to make RGO. PVA, AgNO3, potassium iodide (KI) and CuNO3 were used for the synthesis of composites. All the chemicals used were of AR grade and had been used without anyfurther purification. 2.2 Synthesis of Graphene Oxide/Reduced Graphene Oxide: The GO was synthesized from graphite powder by modified Hummer’s method36 and was reduced by using hydrazine hydrate to make RGO37–39. The GO was prepared by oxidizing graphite with strong acids such as sulphuric acid and hydrogen peroxide which increases interspacing between graphite sheets. Functional groups like epoxide group and hydroxyl group were attached to the sheets of graphite to form graphene oxide and tomake the material suitable for some applications3–6,40. 2.3 Synthesis of PVA-Ag-GO/RGO composites: PVA-GO/RGO composite was prepared by a simple wet chemical method with a calculated amount of GO/RGO, AgNO3 and CuNO3 in PVA matrix. Addition of PVA helped to prevent restacking of sheets of GO and RGO after reduction and in stabilizing the reduced particle suspensions. A solution of 0.0014M CuNO3 and 0.003M



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AgNO3 were mixed in 0.0008M PVA solution and a homogenous solution was made by continuous stirring. A 0.0001 gm/L solution of GO/RGO sheets was prepared separately to make composites. A solution of KI of 0.005M was additionally prepared. After diluting the matrix solution by doubling the amount of deionized (DI) water, the above solution was added to GO/RGO separately in the ratio of 3:2 and was stirred for 30 min. The KI solution was added to the solutions of PVA-Ag-Cu-GO/RGO in the ratio 1:3.33 and was covered with aluminum foil immediately. The covered solution was kept in dark cabinet. To avoid the unwanted exposure to light, the reaction was carried out in the dark. An optimum amount of copper ions were used for the quick photochromic response of the sample. An increased amount of catalyst darkened the sample color when it was exposed to light quickly. However, the sample slowly regained the original color when it was removed from light. 2.4 Mechanism

(Redox reaction) A redox reaction takes place while adding KI solution to AgNO3 and CuNO3 solution. It precipitates cuprous iodide and makes iodine crystal. A little bit of excess KI solution coverts the iodine crystals into a compound KI3, which dissolves into water easily. KI reacts with Ag ion and makes Ag iodide (AgI). The absorption of a photon in AgI excites the electron to transfer from lower to upper band and formation of excitons41. The required energy to produce exciton is not greater than the energy required to produce free electrons and holes in Ag halides. As there is a chance of recombination of these electron-hole pairs, a Cu+ is introduced to capture these holes in the form of CuI. The supply of electron converts the Ag ions into metallic form in a reversible way42. The agglomeration of Ag is eliminated by the introduction of GO/RGO sheets in the 6 ACS Paragon Plus Environment

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composite. This mechanism constitutes the photochromic effect in Ag halides. However, presence of oxygen in the solvent may induce some oxidation of Ag nanoparticles. The formation of the Ag nanoparticles induces plasmonic resonance in the composites. The separation of Ag nanoparticles and graphene basal plane is likely to be influenced by oxide/halide layer which affects the charge separation between the excited electrons and Ag+, and would play an important role in charge transport from photo excited Ag, having consequence in tuning the photochromic response43 due to plasmon shielding. 2.5 Characterization Techniques Ultra violet-Visible (UV-Vis) absorbance spectra were measured using Perkin Elmer Lambda 25 spectrophotometer. The spectra were recorded in the range of 200-800 nm. Transmission Electron Microscopic (TEM) measurements were performed by TEM-JEOL-JEM-2100 operating at an accelerating voltage of 200 kV for the morphological andstructural analysis of the samples. The Raman spectra of all the composites were captured by Raman spectrometer (In Via, Renishaw) using 514.5 nm excitation of continuous Ag+ laser source assisted with a monochromator of 1800 gr/mm and charged coupled device as the detector.

3. RESULTS AND DISCUSSION 3.1 UV-Vis Spectroscopy Figure 1 (a) shows UV-Vis absorption spectra for PVA-Cu-Ag-GO-KI sample before and after its exposure to light for few minutes. It shows the plasmonic peak of Ag nanoparticles at 425 nm. The hybrid of GO/AgI, where AgI may sit on top of the basal plane (as can be seen from TEM micrograph in Figure 6 (a) and (c)), and the edge decoration is not seen to be more than that of the basal plane decoration. The entire hybrid is encapsulated by an optically inert but transparent 7 ACS Paragon Plus Environment


PVA matrix (The refractive index of PVA is ~1.46 to 1.47). The AgI starts getting converted Ag nanoparticles when exposed to light. So, the Ag nanoparticles are expected to be separated from GO by a mixed layer of AgI and PVA. Ag nanoparticles are, however, susceptible to oxidation, which might add up to separating layer. The various functional groups may also contribute to this separator layer. It is known that the SPR response of Ag nanoparticles is sensitive to a surrounding medium. In a theoretical work43, V. Amendola had shown the hybridization of electronic properties in plasmonic nanoparticles near a graphene sheet. The peak position, its intensity, and the spread are the function of its separation from the graphene plane. The graphene also has non-zero absorption in the visible range, which also helps to quench of the plasmonic peak when the separation is within a critical range. Figure1 (b) shows the plasmonic peak for PVA-Cu-Ag-RGO-KI composite at 431 nm. The basal plane of GO and RGO are similar in nature.The amount of various functional groups is the main difference between the two structures, which is less in RGO structure. This may result in more strong interaction for the composite containing RGO. As a result, the red-shift of the plasmonic peak of PVA-Cu-Ag-RGO-KI composite is expected to be more compared to PVAAg-Cu-GO-KI composites, as can be seen from Figures 1(a) & (b). This phenomenon of redshift, quenching of the plasmonic peak, and the spread of the peak, therefore, can be wellunderstood in terms of the work by V. Amendola43. The composite, in fact, is quite sensitive to visible light in general when it is in liquid form and the short exposure to light which is difficult to avoid while performing UV-VIS spectroscopy


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starts converting Ag halide to Ag nanoparticles as is evident from so-called ‘unexposed samples’ which shows a weak plasmonic peak as well. 3.2 Raman Spectroscopy Usually, with the Raman spectroscopy, three effect scan be observed in graphene-based systems, namely the surface effect related enhancement, the splitting of the G, D, and 2D peaks, and the doping-induced shift of the peaks. In our sample, the backbone of the composite is multilayer graphene, with some functional groups, within a polymer matrix, decorated by AgI. These AgI crystals are expected to convert to Ag nanoparticles based on the exposure to light, which in turn canintroduce n-doping in the graphene. The size and inter-particle separation, resulting roughness are expected to be the function of exposure time. The deposition of Ag nanoparticles on graphene introduces a splitting in the Raman peak, which is due to the change in graphene electronic structure44. Apart from this splitting, a stiffening of the G peak is also observable. These changes are introduced due to the presence of charges at the surface and interfaces44. The stiffening in the G peak appears due to the removal of Kohn Anomaly at

point45,46. It is due to

blocking phonon decay into electron-hole pair formation but interlayer interaction reduces the stiffening and sharpening of the G peak46. However, the 2D peak shape and position change are sensitive to doping. It is essentially the second order of the D peak. The D peak originates from the breathing mode of the six atom ring of graphene and can be activated by a defect. The 2D peak, however, does not need any defect for its activation. The appearance of a peak near 1584 cm-1 shows the major feature of the Raman spectra for graphene-based samples which is called G band. The G band for graphene arises due to first order scattering of E2g vibrational mode47–49. The D peak in the Raman spectra arises near 1355 cm-1 due to defect and disorder50. A Raman spectrum of PVA-Cu-Ag-GO-KI composite before 9 ACS Paragon Plus Environment


and after exposure is shown in Figure 2(a). Raman peak of G band shifts towards higher wavenumber with decreased intensity and the Raman peak in the D band shifts toward lower wavenumber with increased intensity for the exposed composite of GO. The G band for PVA-Cu-AgGO-KI composite shifts from 1594 cm-1 to 1603 cm-1 and the D band peak position changes from 1346 cm-1 to 1335 cm-1. The ratios of intensity of the D and the G band before and after the exposure to light are 0.850 and 1.39 respectively. Intense D band in Raman occurs due to the reduction in the size of in-plane domains6. Similarly, the Raman spectra of PVA-Cu-Ag-RGO-KI composite before and after the exposure is shown in Figure 2(b), there is increased up shift in the Raman peak of the G band and the D band for unexposed to exposed samples. The G band peak for PVA-Cu-Ag-RGO-KI composite does not shift from 1594 cm-1 and the D band peak shifts from 1352 cm-1 to 1359 cm-1. The ratios of the peak intensity of the D and the G band before and after the Ag nanoparticle formation are 1.02 and 0.682 respectively. Peak Intensity of D and G bands are increasing significantly after the formation of Ag nanoparticles. This increase in the peak intensity is due to the intense local electromagnetic field of Ag nanoparticles47,51 that associates to plasmon resonance52. The stiffening of G band is also observed for the composite after the formation of Ag nanoparticles. The deconvolved spectra for PVA-Ag-Cu-RGO-KI show the splitting of the G band peak at 1595 cm-1 into two peaks at 1566 cm-1 and 1602 cm-1 for unexposed sample in Figure 3(a) and splitting of the G band peak at 1596 cm-1 into two peaks at 1564 cm-1 and 1602 cm-1after exposure in Figure 3(b). The 2D band of PVA-Cu-Ag-RGO-KI composite before and after exposure to light in the Raman spectra is shown in Figure 4. The Raman intensity of 2D band for RGO composite has been decreased after exposure. The 2D band shifts towards the lower wave-number from 2708 cm-1 to 2690 cm-1 after the formation of Ag nanoparticles when exposed to light. These


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downshift of the 2D band and up shift in the G band shows that the composite has n-type doping on Graphene sheets induced by Ag nanoparticles53. The ratio I2D/IG is maximum at zero doping and reduces with increased doping and the 2D peak is directly connected to the amount of doping. The ratios of intensity of 2D and G bands for PVA-Cu-Ag-RGO-KI composite before and after exposure to light are 0.298 and 0.138 respectively. The Raman bands present in PVA-Ag-Cu-GO/RGO-KI composites before and after the exposure in light are shown in Table 1. The full width half maximum (FWHM) of the 2D, D and G bands for PVA-Cu-Ag-RGO-KI composite before and after exposure to light are changing from 127 to 327 cm-1, from 125 to 184 cm-1 and 110 to 112 cm-1, respectively. The FWHM of the D and G bands for PVA-Cu-Ag-GO-KI composite before and after exposure to lightis changing from 145 to 186 cm-1 and 155 to 120 cm-1, respectively. The intensity ratio of 2D and G bands of Raman spectrum is the measure of the amount of doping54–56. The approximate amounts of doping of GO/RGO sheets in the matrix are of the order of 1011 cm-2. The levels of doping in GO/RGO samples are changing from 1.4 X 1011 to 1.3 X 1011 and 0.7 X 1011 to 0.34 X 1011 cm-2 for before & after exposure respectively. A full range Raman spectrum for PVA-Ag-Cu-GO/RGO-KI samples before and after exposure to light is shown in Figure 7. B-GO, B-RGO & A-GO, A-RGO is indicating PVA-Ag-Cu-GO/RGO-KI samples before and after exposure to light. Photochromic behavior of RGO based composite is observed when the composite is exposed to light for few minutes. Photochromic behavior of composite is shown by the optical image in Figure 5, Photo chromic response of the sample is shown with the change of color in four stages, where stage 1 & 2 shows unexposed and exposed sample. The reversibility of the sample is shown by stage 3 & 4 in figure 5. The photochromic effect of Ag halide is known to be reversible57,58. However, the reaction is “asymmetric” in the



sense of time needed to go forward and backward. The forward movement is much faster whereas in the backward movement in the dark the reaction is slower. The visible inspection of the solution shows the reversibility in a distinct way. 3.3 Transmission Electron Microscopy The microstructure of the composite has been studied with the TEM imaging. It is observed that Ag nanoparticles are homogeneously formed in the PVA matrix and attached to RGO sheets. Figure 6(a) shows that Ag nanoparticles are homogeneously and densely formed on the reduced graphene oxide sheets with average particles size in the range of 3-12 nm. High-Resolution TEM (HRTEM) is shown in Figure 6(c) and the d-spacing (~0.39 nm) of Ag nanoparticles on RGO sheets is shown in Figure 6(b). Histogram plot for the calculated average particle size from TEM is shown in Figure 6(d).

4. CONCLUSION We are able to successfully demonstrate the optically tunable n-doping of PVA-Ag-CuGO/RGO-KI composite and light-induced formation of Ag nanoparticles from Ag halides which has been synthesized through a facile wet chemical method. Ag halide nanoparticles on GO/RGO sheets in polymer matrix show photochromic behavior, which is reversible in nature. The photochromic reaction occurs in the presence of light when Ag halide in presence of copper hole trapper gets reduced to Ag nanoparticles. The presence of Ag nanoparticles is confirmed by the appearance of a plasmonic peak at ~ 425 nm and ~432 nm for the two composites in the UVVis absorption spectra after the exposure of composites in the light. The red-shift, partial quenching, and spread of plasmonic peaks due to formation Ag nanoparticles are due to the strong interaction between the nanoparticle and graphene basal plane inside PVA matrix. The 12 ACS Paragon Plus Environment

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decreased ratio of I2D/IG is observed after the formation of Ag nanoparticles on the RGO sheets, which confirms the n-type doping on the surface. Surface plasmons of these Ag nanoparticles become responsible for tunable doping of GO/RGO sheets in the composite. The approximate amounts of doping of GO/RGO sheets in the matrix are of the order of 1011 cm-2. The large surface area of graphene makes it useful in absorbing the incident light to produce surface plasmons and also helps in the charge transfer to metal halides. Optimized tunable doping is achieved with this simple synthesis of the said composite with controlled exposure.

Acknowledgment Neelam Singh is thankful to G.G.S. Indraprastha University, New Delhi for providing financial assistance in the form of Indraprastha Research Fellowship (IPRF). Authors are also thankful to Center for Research in Nanoscience and Technology, University of Calcutta, India for helping in TEM

measurements

and

for

providing

facilities

under

the

FRGS

grant

(GGSIPU/DRC/Ph.D./Adm./2016/1565) and the grant of DST for FISTgrant (SR/FST/PSI167/2011(C) at GGSIPU. Dr. S. Mandal thanks DST for a grant under DST-FIST SR/FST/College-087 at BGC. AUTHOR INFORMATION *Corresponding Author Email: [email protected]



REFERENCES: (1)

Wang, H.; Maiyalagan, T.; Wang, X. Review on Recent Progress in Nitrogen-Doped Graphene: Synthesis, Characterization, and Its Potential Applications. ACS Catal. 2012, 2 (5), 781–794.

(2)

Oh, J. S.; Kim, K. N.; Yeom, G. Y. Graphene Doping Methods and Device Applications. J. Nanosci. Nanotechnol. 2014, 14 (2), 1120–1133.

(3)

Ren, P.-G.; Yan, D.-X.; Ji, X.; Chen, T.; Li, Z.-M. Temperature Dependence of Graphene Oxide Reduced by Hydrazine Hydrate. Nanotechnology 2011, 22 (5), 055705.

(4)

Georgakilas, V.; Otyepka, M.; Bourlinos, A. B.; Chandra, V.; Kim, N.; Kemp, K. C.; Hobza, P.; Zboril, R.; Kim, K. S. Functionalization of Graphene: Covalent and NonCovalent Approaches, Derivatives and Applications. Chem. Rev. 2012, 112 (11), 6156– 6214.

(5)

Ramanathan, T.; Abdala, A. A.; Stankovich, S.; Dikin, D. A.; Herrera-Alonso, M.; Piner, R. D.; Adamson, D. H.; Schniepp, H. C.; Chen, X.; Ruoff, R. S.; et al. Functionalized Graphene Sheets for Polymer Nanocomposites. Nat. Nanotechnol. 2008, 3 (6), 327–331.

(6)

Geim, A. K.; Novoselov, K. S. The Rise of Graphene. Nat. Mater. 2007, 6 (3), 183–191.

(7)

Kim, K. S.; Zhao, Y.; Jang, H.; Lee, S. Y.; Kim, J. M.; Kim, K. S.; Ahn, J.-H.; Kim, P.; Choi, J.-Y.; Hong, B. H. Large-Scale Pattern Growth of Graphene Films for Stretchable Transparent Electrodes. Nature 2009, 457 (7230), 706–710.

(8)

Falkovsky, L. A. Optical Properties of Graphene. J. Phys. Conf. Ser. 2008, 129, 012004.

(9)

Wang, H.; Wang, Q.; Cheng, Y.; Li, K.; Yao, Y.; Zhang, Q.; Dong, C.; Wang, P.; Schwingenschlögl, U.; Yang, W.; et al. Doping Monolayer Graphene with Single Atom Substitutions. Nano Lett .2012, 12 (1), 141–144.


Page 14 of 32

Page 15 of 32 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(10) Li, Y.; Zhou, Z.; Shen, P.; Chen, Z. Spin Gapless Semiconductor−Metal−Half-Metal Properties in Nitrogen-Doped Zigzag Graphene Nanoribbons. ACS Nano 2009, 3 (7), 1952–1958. (11) Biel, B.; Blase, X.; Triozon, F.; Roche, S. Anomalous Doping Effects on Charge Transport in Graphene Nanoribbons. Phys. Rev. Lett. 2009, 102 (9). (12) Qu, L.; Liu, Y.; Baek, J.-B.; Dai, L. Nitrogen-Doped Graphene as Efficient Metal-Free Electrocatalyst for Oxygen Reduction in Fuel Cells. ACS Nano 2010, 4 (3), 1321–1326. (13) Reddy, A. L. M.; Srivastava, A.; Gowda, S. R.; Gullapalli, H.; Dubey, M.; Ajayan, P. M. Synthesis Of Nitrogen-Doped Graphene Films For Lithium Battery Application. ACS Nano 2010, 4 (11), 6337–6342. (14) Liu, C.; Yu, Z.; Neff, D.; Zhamu, A.; Jang, B. Z. Graphene-Based Supercapacitor with an Ultrahigh Energy Density. Nano Lett. 2010, 10 (12), 4863–4868. (15) Stoller, M. D.; Park, S.; Zhu, Y.; An, J.; Ruoff, R. S. Graphene-Based Ultracapacitors. Nano Lett. 2008, 8 (10), 3498–3502. (16) Sheng, Z.-H.; Shao, L.; Chen, J.-J.; Bao, W.-J.; Wang, F.-B.; Xia, X.-H. Catalyst-Free Synthesis of Nitrogen-Doped Graphene via Thermal Annealing Graphite Oxide with Melamine and Its Excellent Electrocatalysis. ACS Nano 2011, 5 (6), 4350–4358. (17) Kang, X.; Wang, J.; Wu, H.; Aksay, I. A.; Liu, J.; Lin, Y. Glucose Oxidase–Graphene– Chitosan Modified Electrode for Direct Electrochemistry and Glucose Sensing. Biosens. Bioelectron. 2009, 25 (4), 901–905. (18) Beams, R.; Gustavo Cançado, L.; Novotny, L. Raman Characterization of Defects and Dopants in Graphene. J. Phys. Condens. Matter 2015, 27 (8), 083002.



(19) Rao, C. N. R.; Voggu, R. Charge-Transfer with Graphene and Nanotubes. Mater. Today 2010, 13 (9), 34–40. (20) Panchakarla, L. S.; Subrahmanyam, K. S.; Saha, S. K.; Govindaraj, A.; Krishnamurthy, H. R.; Waghmare, U. V.; Rao, C. N. R. Synthesis, Structure, and Properties of Boron- and Nitrogen-Doped Graphene. Adv. Mater. 2009, NA-NA. (21) Voggu, R.; Das, B.; Rout, C. S.; Rao, C. N. R. Effects of Charge Transfer Interaction of Graphene with Electron Donor and Acceptor Molecules Examined Using Raman Spectroscopy and Cognate Techniques. J. Phys. Condens. Matter 2008, 20 (47), 472204. (22) Bolotin, K. I.; Sikes, K. J.; Hone, J.; Stormer, H. L.; Kim, P. Temperature-Dependent Transport in Suspended Graphene. Phys. Rev. Lett. 2008, 101 (9). (23) Bolotin, K. I.; Sikes, K. J.; Jiang, Z.; Klima, M.; Fudenberg, G.; Hone, J.; Kim, P.; Stormer, H. L. Ultrahigh Electron Mobility in Suspended Graphene. Solid State Commun. 2008, 146 (9–10), 351–355. (24) Son, Y.-W.; Cohen, M. L.; Louie, S. G. Half-Metallic Graphene Nanoribbons. Nature 2006, 444 (7117), 347–349. (25) Trauzettel, B.; Bulaev, D. V.; Loss, D.; Burkard, G. Spin Qubits in Graphene Quantum Dots. Nat. Phys. 2007, 3 (3), 192–196. (26) Balandin, A. A.; Ghosh, S.; Bao, W.; Calizo, I.; Teweldebrhan, D.; Miao, F.; Lau, C. N. Superior Thermal Conductivity of Single-Layer Graphene. Nano Lett. 2008, 8 (3), 902– 907. (27) Wei, D.; Liu, Y.; Wang, Y.; Zhang, H.; Huang, L.; Yu, G. Synthesis of N-Doped Graphene by Chemical Vapor Deposition and Its Electrical Properties. Nano Lett. 2009, 9 (5), 1752–1758.


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(28) Jin, Z.; Yao, J.; Kittrell, C.; Tour, J. M. Large-Scale Growth and Characterizations of Nitrogen-Doped Monolayer Graphene Sheets. ACS Nano 2011, 5 (5), 4112–4117. (29) Guo, B.; Liu, Q.; Chen, E.; Zhu, H.; Fang, L.; Gong, J. R. Controllable N-Doping of Graphene. Nano Lett. 2010, 10 (12), 4975–4980. (30) Castro, E. V.; Novoselov, K. S.; Morozov, S. V.; Peres, N. M. R.; dos Santos, J. M. B. L.; Nilsson, J.; Guinea, F.; Geim, A. K.; Neto, A. H. C. Biased Bilayer Graphene: Semiconductor with a Gap Tunable by the Electric Field Effect. Phys. Rev. Lett. 2007, 99 (21). (31) Zhou, S. Y.; Gweon, G.-H.; Fedorov, A. V.; First, P. N.; de Heer, W. A.; Lee, D.-H.; Guinea, F.; Castro Neto, A. H.; Lanzara, A. Substrate-Induced Bandgap Opening in Epitaxial Graphene. Nat. Mater. 2007, 6 (10), 770–775. (32) Ferrari, A. C.; Meyer, J. C.; Scardaci, V.; Casiraghi, C.; Lazzeri, M.; Mauri, F.; Piscanec, S.; Jiang, D.; Novoselov, K. S.; Roth, S.; et al. Raman Spectrum of Graphene and Graphene Layers. Phys. Rev. Lett. 2006, 97 (18). (33) Malard, L. M.; Nilsson, J.; Elias, D. C.; Brant, J. C.; Plentz, F.; Alves, E. S.; Castro Neto, A. H.; Pimenta, M. A. Probing the Electronic Structure of Bilayer Graphene by Raman Scattering. Phys. Rev. B 2007, 76 (20). (34) Ni, Z. H.; Yu, T.; Lu, Y. H.; Wang, Y. Y.; Feng, Y. P.; Shen, Z. X. Uniaxial Strain on Graphene: Raman Spectroscopy Study and Band-Gap Opening. ACS Nano 2008, 2 (11), 2301–2305. (35) Khan, M. E.; Khan, M. M.; Cho, M. H. Environmentally Sustainable Biogenic Fabrication of AuNP Decorated-Graphitic g-C

3

N

4

Nanostructures towards Improved

Photoelectrochemical Performances. RSC Adv. 2018, 8 (25), 13898–13909.



(36) Hummers, W. S.; Offeman, R. E. Preparation of Graphitic Oxide. J. Am. Chem. Soc. 1958, 80 (6), 1339–1339. (37) Abdolhosseinzadeh, S.; Asgharzadeh, H.; Seop Kim, H. Fast and Fully-Scalable Synthesis of Reduced Graphene Oxide. Sci. Rep. 2015, 5 (1). (38) Kim, H.; Abdala, A. A.; Macosko, C. W. Graphene/Polymer Nanocomposites. Macromolecules 2010, 43 (16), 6515–6530. (39) Mitra, S.; Mondal, O.; Saha, D. R.; Datta, A.; Banerjee, S.; Chakravorty, D. Magnetodielectric Effect in Graphene-PVA Nanocomposites. J. Phys. Chem. C 2011, 115 (29), 14285–14289. (40) Stankovich, S.; Dikin, D. A.; Dommett, G. H. B.; Kohlhaas, K. M.; Zimney, E. J.; Stach, E. A.; Piner, R. D.; Nguyen, S. T.; Ruoff, R. S. Graphene-Based Composite Materials. Nature 2006, 442 (7100), 282–286. (41) Bose, D. N.; Govindacharyulu, P. A. Physics of Silver Halides and Their Applications. Bull. Mater. Sci. 1980, 2 (4), 221–231. (42) Armistead, W. H.; Stookey, S. D. Photochromic Silicate Glasses Sensitized by Silver Halides. Science 1964, 144 (3615), 150–154. (43) Amendola, V. Surface Plasmon Resonance of Silver and Gold Nanoparticles in the Proximity of Graphene Studied Using the Discrete Dipole Approximation Method. Phys. Chem. Chem. Phys. 2016, 18 (3), 2230–2241. (44) Stampfer, C.; Molitor, F.; Graf, D.; Ensslin, K.; Jungen, A.; Hierold, C.; Wirtz, L. Raman Imaging of Doping Domains in Graphene on SiO2. Appl. Phys. Lett. 2007, 91 (24), 241907.


Page 18 of 32

Page 19 of 32 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(45) Basko, D. M.; Piscanec, S.; Ferrari, A. C. Electron-Electron Interactions and Doping Dependence of the Two-Phonon Raman Intensity in Graphene. Phys. Rev. B 2009, 80 (16). (46) Das, A.; Pisana, S.; Chakraborty, B.; Piscanec, S.; Saha, S. K.; Waghmare, U. V.; Novoselov, K. S.; Krishnamurthy, H. R.; Geim, A. K.; Ferrari, A. C.; et al. Monitoring Dopants by Raman Scattering in an Electrochemically Top-Gated Graphene Transistor. Nat. Nanotechnol. 2008, 3 (4), 210–215. (47) Çiplak, Z.; Yildiz, N.; Çalimli, A. Investigation of Graphene/Ag Nanocomposites Synthesis Parameters for Two Different Synthesis Methods. Fuller. Nanotub. Carbon Nanostructures2015, 23 (4), 361–370. (48) Allen, M. J.; Tung, V. C.; Kaner, R. B. Honeycomb Carbon: A Review of Graphene. Chem. Rev. 2010, 110 (1), 132–145. (49) Gao, J.; Liu, F.; Liu, Y.; Ma, N.; Wang, Z.; Zhang, X. Environment-Friendly Method To Produce Graphene That Employs Vitamin C and Amino Acid. Chem. Mater. 2010, 22 (7), 2213–2218. (50) Pimenta, M. A.; Dresselhaus, G.; Dresselhaus, M. S.; Cançado, L. G.; Jorio, A.; Saito, R. Studying Disorder in Graphite-Based Systems by Raman Spectroscopy. Phys. Chem. Chem. Phys. 2007, 9 (11), 1276–1290. (51) Li, J.; Liu, C. Ag/Graphene Heterostructures: Synthesis, Characterization and Optical Properties. Eur. J. Inorg. Chem. 2010, 2010 (8), 1244–1248. (52) Nguyen, V. H.; Kim, B.-K.; Jo, Y.-L.; Shim, J.-J. Preparation and Antibacterial Activity of Silver Nanoparticles-Decorated Graphene Composites. J. Supercrit. Fluids 2012, 72, 28– 35.



(53) Dhibar, S.; Das, C. K. Silver Nanoparticles Decorated Polypyrrole/Graphene Nanocomposite: A Potential Candidate for next-Generation Supercapacitor Electrode Material. J. Appl. Polym. Sci. 2017, 134 (16). (54) Cançado, L. G.; Jorio, A.; Ferreira, E. H. M.; Stavale, F.; Achete, C. A.; Capaz, R. B.; Moutinho, M. V. O.; Lombardo, A.; Kulmala, T. S.; Ferrari, A. C. Quantifying Defects in Graphene via Raman Spectroscopy at Different Excitation Energies. Nano Lett. 2011, 11 (8), 3190–3196. (55) Rao, C. N. R.; Sood, A. K.; Subrahmanyam, K. S.; Govindaraj, A. Graphene: The New Two-Dimensional Nanomaterial. Angew. Chem. Int. Ed. 2009, 48 (42), 7752–7777. (56) Bruna, M.; Ott, A. K.; Ijäs, M.; Yoon, D.; Sassi, U.; Ferrari, A. C. Doping Dependence of the Raman Spectrum of Defected Graphene. ACS Nano 2014, 8 (7), 7432–7441. (57) Miyazaki, H.; Shimoguchi, H.; Nakayama, H.; Suzuki, H.; Ota, T. Effects of Excess Cu Addition on Photochromic Properties of AgCl-Urethane Resin Composite Films. Adv. Mater. Sci. Eng. 2013, 2013, 1–5. (58) Mennig, M.; Schmidt, H. K.; Fink-Straube, C. Synthesis and Properties of Sol-GelDerived AgClxBr1-x Colloid Containing Sodium Alumo Borosilicate Glasses; Bray, P., Kreidl, N. J., Eds.; Boston, United States, 1991, 152–159.


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List of Tables and Figure Captions, and Figures

Table 1: Raman bands present in PVA-Ag-Cu-GO/RGO-KI composites before and after the exposure of composites in the light.

Figure Captions Figure 1: UV-Vis spectrum of exposed and unexposed samples of (a) PVA-Ag-Cu-GO-KI composites, (b) PVA-Ag-Cu-RGO-KI composites. Figure 2: D andG bands in theRaman spectra of the sample before and after the exposure of samples to light. (a) PVA-Ag-Cu-GO-KI sample (b) PVA-Ag-Cu-RGO-KI sample Figure 3: (a) The deconvolved spectra of G bands of RGO based composite before exposure to light and (b) after exposure to light. Figure 4: 2D bands in the Raman spectra of RGO sample before and after exposure of samples to light. Figure 5: Photograph of the composite beforeand after exposure to light. Figure 6: (a) TEM image (b) HRTEM image showing d-spacing of Ag nanoparticles in the (c) composite (d) Histogram of composite showing distribution of particle size.



Figure 7: The Raman spectra of PVA-Ag-Cu-GO/RGO-KI samples before and after exposure to light. B-GO, B-RGO & A-GO, A-RGO is indicating PVA-Ag-Cu-GO/RGO-KI samples before and after exposure to light.

FIGURES

Figure 1

Figure 2


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Figure 3

Figure 4



Figure 5

Figure 6


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Figure 7



TOC GRAPHICS


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TOC Graphic 236x185mm (96 x 96 DPI)

ACS Paragon Plus Environment


Figures

Figure 1

Figure 2


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Figure 3

Figure 4



Figure 5

Figure 6


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Figure 7



Table 1


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RGO Sheets

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