Hypervalent Iodine Compounds as Versatile Reagents for Extremely Efficient and Reversible Patterning of Graphene with Nanoscale Precision
←
→
Page content transcription
If your browser does not render page correctly, please read the page content below
Research Article
www.advmat.de
Hypervalent Iodine Compounds as Versatile Reagents
for Extremely Efficient and Reversible Patterning
of Graphene with Nanoscale Precision
Lipiao Bao, Baolin Zhao, Bowen Yang, Marcus Halik, Frank Hauke, and Andreas Hirsch*
1. Introduction
Rational patterning and tailoring of graphene relies on the disclosure of
suitable reagents for structuring the target functionalities on the 2D-carbon Covalent 2D patterning of distinct func-
network. Here, a series of hypervalent iodine compounds, namely, 1-chloro- tionalities on the graphene framework is
1,2-benziodoxol-3(1H)-one, 1,3-dihydro-1-hydroxy-3,3-dimethyl-1,2-benzio- crucial for engineering the multifaceted
surface properties of graphene for spe-
doxole, and 3,3-dimethyl-1-(trifluoromethyl)-1,2-benziodoxole is reported to be
cific demands in such fields as molecular
extremely efficient for a diversified graphene patterning. The decomposition of electronics, energy storage/conversion,
these compounds generates highly reactive Cl, OH, and CF3 radicals exclu- and catalysis.[1–7] Key to this challenging
sively in the irradiated areas, which subsequently attach onto the graphene task is the establishment of efficient
leading to locally controlled chlorination, hydroxylation, and trifluoromethyla- functionalization reagents in combina-
tion with suitable patterning techniques
tion, respectively. This is the first realization of a patterned hydroxylation of
to direct target addends in a well-defined
graphene, and the degrees of functionalization of the patterned chlorination order on the 2D carbon lattice. In pre-
and trifluoromethylation are both unprecedented. The usage of these mild rea- ceding reports, four main approaches for
gents here is reasonably facile compared to the reported methods using haz- graphene patterning have been demon-
ardous Cl2 or ICl and allows for sophisticated pattern designs with nanoscale strated, namely, laser/plasma writing,[8–11]
precision, promising for arbitrary nanomanipulation of graphene’s properties poly(methyl methacrylate) (PMMA)-
assisted lithography,[12–15] force-accelerated
like hydrophilicity and conductivity by the three distinct functionalities (Cl,
patterning,[16] and space-controlling by
OH, and CF3). Moreover, the attachment of functional entities to these highly self-assembly.[17–19] Recently, our group
functionalized graphene nanoarchitectures is fully reversible upon thermal has considerably improved the efficiency
annealing, enabling a full writing/storing/reading/erasing control over the of graphene patterning by importing a
chemical information stored within graphene. This work provides an exciting pre-activation treatment using a K/Na
alloy[11,15,20] or by the implementation of
clue for target 2D functionalization and modulation of graphene by using suit-
AgF for the bottom-side fluorination via
able hypervalent iodine compounds. our newly developed 2D substrate pat-
terning protocol.[21] Among these pat-
terning approaches the simple and
Dr. L. Bao, B. Yang, Dr. F. Hauke, Prof. A. Hirsch straightforward laser writing method stands out as it bears a
Department of Chemistry and Pharmacy, Joint Institute of Advanced number of clear advantages: I) arbitrary pattern design in large
Materials and Processes (ZMP)
scale, II) easy-to-access due to the wide range of available laser
Friedrich-Alexander University of Erlangen-Nürnberg
Nikolaus-Fiebiger-Strasse 10, 91058 Erlangen, Germany technology, III) facile patterning procedure without compli-
E-mail: andreas.hirsch@fau.de cated lithography processes including the required removal of
B. Zhao, Prof. M. Halik the mask, and IV) capability of the in situ investigation of the
Organic Materials and Devices (OMD) functionalization process by using the lasers directly integrated
Institute for Polymer Materials in the commercial Raman setup. However, a fatal flaw of this
Interdisciplinary Center for Nanostructured Films (IZNF)
Friedrich-Alexander University of Erlangen-Nürnberg approach is the lack of suitable photosensitive reagents. To
Cauerstraße 3, 91058 Erlangen, Germany date, only three preceding examples of laser-induced graphene
The ORCID identification number(s) for the author(s) of this article patterning have been reported, namely, benzoyl peroxides (haz-
can be found under https://doi.org/10.1002/adma.202101653. ardous),[10,11,22] a specific fluoropolymer (CYTOP),[8] and silver
trifluoroacetate.[23] At the same time, using benzoyl peroxides
© 2021 The Authors. Advanced Materials published by Wiley-VCH
GmbH. This is an open access article under the terms of the Creative for the laser writing allow only for the establishment of rela-
Commons Attribution-NonCommercial-NoDerivs License, which tively low degrees of functionalization—located in the low func-
permits use and distribution in any medium, provided the original work tionalization regime of the Cançado curve[24]—requiring also
is properly cited, the use is non-commercial and no modifications or rather extended long irradiation periods.[10,11,22] Despite the rela-
adaptations are made.
tively high degree of functionalization provided by the CYTOP
DOI: 10.1002/adma.202101653 polymer and silver trifluoroacetate, their post-patterning
Adv. Mater. 2021, 33, 2101653 2101653 (1 of 9) © 2021 The Authors. Advanced Materials published by Wiley-VCH GmbH
www.advancedsciencenews.com www.advmat.de removal remains a severe challenge, which is difficult to over- laser (see the Experimental Section for the details) was directed come when targeting the high standards for real applications onto the graphene sample to trigger the decomposition of the of graphene nanoarchitectures. Specifically, the removal of reagents, which generates highly reactive Cl, OH, and CF3 radi- polymer CYTOP requires not only a special stripper but also cals for ClBO, HOBO, and MFBO, respectively, exclusively at a very long time,[8] and the usage of silver trifluoroacetate una- the irradiated regions. It should be noted that although the three voidably generates in situ conductive silver nanoparticles at the compounds have seemingly no absorption at 532 nm (Figure S3, patterned areas, which restricts the applications, for example, Supporting Information), the graphene itself could serve as the in electronics.[23] Another even more important aspect of gra- photomediator for the reactions as it has absorption in the vis- phene patterning is the capability of the grafted addends to ible range.[32] Addition of these radicals onto the irradiated gra- modulate the properties of the modified graphene since this is phene areas leads to a selective chlorination, hydroxylation, and directly correlated with the final applications of these graphene trifluoromethylation of graphene, respectively. After the writing, nanostructures. Studies in this direction are still very scarce, the organic layer of these residual reagents on graphene was and the only existing examples are targeted on either electronic removed by washing, affording three graphene nanostructures structures alteration[8,19,25] or surface potential modulation.[12,14] denoted as fG-Cl, fG-OH, and fG-CF3, respectively. As such, developing new functionalization reagents that can The functionalization processes were monitored with in situ provide not only a very high degree of functionalization but also Raman spectroscopy as we also use the laser directly equipped versatile property tuning abilities (e.g., hydrophilicity and con- in the Raman instrument for the writing. The Raman spectra ductivity) is highly desired. along with the corresponding ID/IG profile located on the Can- Herein, we report on a series of hypervalent iodine com- çado curve[24] as a function of the laser irradiation time are pounds,[26,27] namely, 1-chloro-1,2-benziodoxol-3(1H)-one (ClBO), depicted in Figure 2. Clearly, all three graphene samples coated 1,3-dihydro-1-hydroxy-3,3-dimethyl-1,2-benziodoxole (HOBO), with the respective hypervalent iodine reagents can undergo and 3,3-dimethyl-1-(trifluoromethyl)-1,2-benziodoxole (MFBO), a laser-triggered functionalization and the degree of function- for an extremely efficient and reversible 2D patterning of gra- alization depends on the laser irradiation time. For the sample phene. The ICl, IOH, and ICF3 bonds in these three pre- coated with HOBO, a pronounced D-band has been detected cursor compounds are rather weak and therefore their homol- after irradiation for 45 s (Figure 2c,d). The generation of a ysis easily takes place under laser irradiation. The resulting Cl, D-band is indicative for the bonding transformation from sp2 to OH, and CF3 radicals are highly reactive and can subsequently sp3 hybridization as a result of the covalent functionalization of undergo addition reactions onto the inert graphene surface graphene by OH radicals. Further increasing the laser irradia- exclusively at the irradiated regions. This leads to the first tion time to 270 s leads to a very high degree of hydroxylation example of patterned hydroxylation of graphene. In situ studies with an ID/IG ratio of 2.8 compared to
www.advancedsciencenews.com www.advmat.de Figure 1. a) The antaratopic binding topology of the functionalized graphene sample. b) The hypervalent iodine compounds used for graphene pat- terning in this work. c) Schematic illustration of the graphene 2D-patterning process (left column) and the corresponding microscopy images of the graphene sample at each step (right columns). I) A layer of the respective reagent was coated onto a monolayer graphene supported by a SiO2/Si wafer. II) Laser writing with a green laser (λ = 532 nm, see the Experimental Section for the detailed parameters) on predefined regions generated highly reactive radical intermediates (Cl, OH, and CF3 radicals for ClBO, HOBO, and MFBO, respectively) which subsequently added onto the graphene surface. III) The residual reagent layer was removed yielding the corresponding patterned graphene samples denoted as fG-Cl, fG-OH, and fG-CF3, respectively. Scale bars = 5 µm. trifluoroacetate.[23] The trifluoromethylation nature is also veri- patterned chlorination and trifluoromethylation, highlighting fied by the continuously increased upshift of the G-band cor- the superiority of the developed hypervalent iodine compounds relating with the laser time (Figure 2e) due to the electron-with- for the diversified graphene patterning. drawing property of the CF3 group. To obtain an overall impres- A precise control over the degree of functionalization and sion of the extraordinary efficiency of these hypervalent iodine reaction areas leads to the patterned functionalization of compounds for the diversified graphene patterning, we quanti- each sample. Specifically, triangle, quadrangle, and pentagon fied and compared the degree of functionalization realized in designs (Figure S1, Supporting Information, for the detailed this work and preceding reports. As can be seen from Table S1, irradiation profiles) are written on fG-Cl, fG-OH, and fG-CF3 the degree of chlorination obtained here is ≈25 times of the using ClBO, HOBO, and MFBO as the reactant, respectively values in the two reported cases using ICl or Cl2[33,35] and the (Figure 1). The graphene samples at each step can be visual- degree of trifluoromethylation by MFBO represents the highest ized from the corresponding microscopy images (Figure 1c). degree of functionalization that has been realized for graphene For fG-Cl and fG-OH, the patterned design can be directly dis- patterning. Hence, using the three hypervalent iodine com- tinguished from the microscopy images after the writing step. pounds here as the reactants for graphene patterning leads not Besides, the patterned structures can also be deduced from only to the first patterned hydroxylation of graphene but also the image after washing, where the irradiated regions show a to unprecedentedly high degrees of functionalization for the higher transparency compared to the unfunctionalized areas. Adv. Mater. 2021, 33, 2101653 2101653 (3 of 9) © 2021 The Authors. Advanced Materials published by Wiley-VCH GmbH
www.advancedsciencenews.com www.advmat.de Figure 2. a,c,e) Raman spectrum of the monolayer graphene coated with ClBO (a), HOBO (c), and MFBO (e). b,d,f) The corresponding ID/IG profile located on the Cançado curve[24] for the monolayer graphene coated with ClBO (b), HOBO (d), and MFBO (f). LD: the mean distance between defects. The pink and blue dashed lines indicate the positions of the G-band (1585 cm−1) and 2D-band (2676 cm−1) of the starting monolayer graphene, respec- tively. λexc = 532 nm. A similar increase in the transparency of graphene, based on laser powers (see Table S2 for details) which consumes only a the implementation of a high covalent addend loading, has trace amount of the reagent so that no obvious morphological also been reported for extensively fluorinated graphene,[36] and changes in the covering film of MFBO could be detected opti- this is a clear indication that in our case an extraordinary high cally (Figure S2, Supporting Information). Besides, we cannot amount of chlorine and hydroxyl functions have been attached observe similar transparency increase of graphene like in the to the graphene sheet in the case of fG-Cl and fG-OH, respec- cases of fG-Cl and fG-OH. In this regard, our results indicate tively. The case of fG-CF3 is a little bit different where the pen- visually no transparency change of graphene upon trifluoro- tagon pattern cannot be directly visualized from the respective methylation despite a very high degree of functionalization microscopy images. This could be due to the very high rate realized here. In Figure 3, the respective Raman mean spectra of functionalization in the case of fG-CF3, even at very low and the corresponding statistical Raman ID/IG histograms are Adv. Mater. 2021, 33, 2101653 2101653 (4 of 9) © 2021 The Authors. Advanced Materials published by Wiley-VCH GmbH
www.advancedsciencenews.com www.advmat.de Figure 3. a) Mean Raman spectra and b) statistical Raman ID/IG histogram of the respective graphene sample before and after laser irradiation. The pink and blue dashed lines indicate the positions of the G-band (1585 cm−1) and 2D-band (2676 cm−1) of the starting monolayer graphene, respectively. λexc = 532 nm. presented. Clearly, the non-irradiated area shows—for all three units has been further corroborated by the upshift of 2D-band samples—a Raman spectrum resembling that of the pristine (Figures 2 and 3 and Figure S6, Supporting Information).[31,37] graphene with an ID/IG ratio of
www.advancedsciencenews.com www.advmat.de Figure 5. a–c) KPFM images of fG-Cl (a), fG-OH (b), and fG-CF3 (c). d) SEM image and e) elemental distribution of Cl of fG-Cl. f) The corresponding surface potential profiles of fG-Cl, fG-OH, and fG-CF3. Scale bars = 5 µm. fG-CF3, respectively, Figure 1c and Figure S1, Supporting Infor- the elemental distribution of Cl in fG-Cl (Figure 5e) matches mation). In addition to the complicated pattern design dem- very well with the pattern designs (Figure 1 and Figure S1, onstrated here, our patterned functionalization using these Supporting Information) and the Raman ID/IG mappings hypervalent iodine compounds via laser writing provides a (Figure 4a). In addition, the surface electrostatic potentials of very high resolution down to the nanometer level. As shown in the patterned areas in fG-Cl, fG-OH, and fG-CF3 are higher than Figure 4d,e, after the writing of parallel lines (perpendicular dis- the undisturbed areas by significant differences of 30, 80, and tances: 1 µm) on graphene using HOBO and the removal of the 110 mV, respectively (Figure 5f), representing even more pow- residual HOBO, the acquired Raman D-band mapping demon- erful capabilities for the surface potential modulation of gra- strates the very high precision of ≈200 nm. As the degree of phene in comparison to the two reported cases using diazonium functionalization and pattern design can be facilely controlled (≈74 mV)[12] and Diels−Alder (≈100 mV)[14] reactions. The distinct at the nanometer level by tuning the laser time and pathway, differences of surface potentials give rise to clear images of these any desired graphene nanostructures with spatially defined Cl, chemical patterns (Figure 5a–c for fG-Cl, fG-OH, and fG-CF3, OH, or CF3 groups can be easily fabricated with nanoscale pre- respectively), which is in perfect agreement with our input pat- cision. Considering the property-tuning ability of Cl, OH, and tern designs (Figure 1 and Figure S1, Supporting Information) CF3 (e.g., hydrophilicity and conductivity) as well as the poten- as well as the respective Raman ID/IG mappings (Figure 4). In tial derivatization of Cl and OH groups,[21,28] the possibilities parallel with the accurate pattern design, the nanoscale preci- are numerous and very exciting. sion of ≈200 nm realized in this work was further demonstrated The highly efficient patterned functionalization, together with by the KPFM characterization by showing a sharp pattern edge the precise modulation of the surface properties of graphene, in the surface potential line profiles (Figure 5f). Therefore, provided by these hypervalent iodine compounds, were further these results unambiguously demonstrate the diversified and corroborated by Kelvin probe force microscopy (KPFM) and scan- extremely efficient capabilities provided by these hypervalent ning electron microscopy coupled with energy-dispersive X-ray iodine compounds for not only patterned functionalization but spectroscopy (SEM-EDS). In principle, successful patterned chlo- also surface property modulation of graphene. rination, hydroxylation, and trifluoromethylation should lead not To verify the reversibility and thermal stability of the gra- only to the covalent attachment of the respective addends onto phene nanoarchitectures fG-Cl, fG-OH, and fG-CF3, tempera- the patterned regions but also to a change of surface properties of ture-dependent Raman studies were carried out. As illustrated the corresponding graphene areas, owing to the strong electron- in Figure 6, the increase of the temperature leads to the decline withdrawing abilities of Cl, OH, and CF3 addends. As expected, of the intensity of the D-band for all three samples. This is Adv. Mater. 2021, 33, 2101653 2101653 (6 of 9) © 2021 The Authors. Advanced Materials published by Wiley-VCH GmbH
www.advancedsciencenews.com www.advmat.de Figure 6. Temperature-dependent Raman spectra of a) fG-Cl, b) fG-OH, and c) fG-CF3. d) Mean Raman ID/IG ratios extracted from the respective temperature-dependent Raman spectra. λexc = 532 nm. directly correlated with a reversible sp3–sp2 rehybridization of storing/reading/erasing control over the chemical information lattice carbon atoms accompanied by the detachment of the on graphene. covalently linked addends. The defuctionalization processes occur mainly at 200–350 °C and finish upon increasing the temperature to 450 °C. This complete reversibility of our gra- 3. Conclusion phene nanoarchitectures provides the opportunity to fine-tune the attached entities and the degrees of functionalization by A series of hypervalent iodine compounds, namely, 1-chloro-1,2-ben- thermal annealing. Considering the direct relationship of the ziodoxol-3(1H)-one, 1,3-dihydro-1-hydroxy-3,3-dimethyl-1,2-benzio- attached functionalities with the properties of graphene (e.g., doxole, and 3,3-dimethyl-1-(trifluoromethyl)-1,2-benziodoxole, has hydrophilic and electronic properties), this simple thermal been demonstrated to be extremely efficient for the covalent 2D treatment could serve as another important approach for the patterning of graphene. This uses the rather weak ICl, IOH, precise property manipulation of graphene nanosystems, in and ICF3 bonds in the three precursor hypervalent iodine addition to the control over the laser time/pathway as demon- compounds and their consequent homolysis under light irradia- strated above. tion. The afforded Cl, OH, and CF3 radicals are highly reactive, To demonstrate the controllability of the overall chemical which subsequently undergo addition reaction onto graphene pattern by thermal annealing, the three graphene samples exclusively at the irradiated regions. The degree of functionaliza- were annealed at two specific temperatures: 250 and 450 °C. tion and the design of the patterns with nanoscale precision can As depicted in Figure 7a–c, chemical patterns can still be rec- be facilely manipulated by tuning the laser irradiation time and ognized after annealing at 250 °C (Figure 4) and the overall pathway, leading to the first patterned hydroxylation of graphene degrees of functionalization were adjusted to lower values and unprecedentedly high degrees of patterned chlorination and with ID/IG ratios of ≈0.7–1.0, in comparison to the values prior trifluoromethylation of graphene. The success of the laser-based to the thermal treatment (ID/IG ratios of ≈2.8). A subsequent attachment of functional entities on graphene and the generation rise of the temperature to 450 °C results in the complete of the respective nanoarchitectures was unequivocally demon- defunctionalization and removal of the chemical patterns for strated by Raman, KPFM, and SEM-EDS measurements. More- all three graphene samples, as can be observed in Figure 7d–f. over, the patterned binding of functional moieties is completely Therefore, with our laser writing, Raman mapping, and reversible upon thermal treatment, enabling a full writing/storing/ thermal treatment sequences, we can enable a full writing/ reading/erasing control over chemical information on graphene. Adv. Mater. 2021, 33, 2101653 2101653 (7 of 9) © 2021 The Authors. Advanced Materials published by Wiley-VCH GmbH
www.advancedsciencenews.com www.advmat.de
Figure 7. a–f) Raman ID/IG mapping of fG-Cl (a), fG-OH (b), and fG-CF3 (c) after thermal annealing at 250 °C, and of fG-Cl (d), fG-OH (e), and fG-CF3
(f) after thermal annealing at 450 °C. λexc = 532 nm. Scale bars = 5 µm.
In terms of the strong hydrophilicity of OH unit and hydropho- subjected to the laser writing experiments. fG-CF3 with a pentagon
bicity of Cl and CF3 groups, manipulation of the hydrophilicity of pattern was prepared by laser writing using a green laser (532 nm,
0.25 mW, 100× objective, 2 s, 0.5 µm step size) and subsequent washing
the graphene architectures at the nanometer level would be simple
with dichloromethane as well as drying with argon.
and straightforward by our methods reported here, of which many
exciting applications like in biology (e.g., cell micropatterning[38,39])
could be envisaged. Moreover, considering the wide variety of
hypervalent iodine compounds, and the subsequent secondary Supporting Information
derivatization of the attached Cl and OH moieties, our results pro- Supporting Information is available from the Wiley Online Library or
vide numerous opportunities for arbitrary patterning and property from the author.
tailoring (e.g., hydrophilicity and conductivity) of graphene at the
nanometer level.
Acknowledgements
This work was funded by the Deutsche Forschungsgemeinschaft (DFG,
4. Experimental Section German Research Foundation) (Project ID: 182849149 – SFB 953). B.Z.
is grateful for the financial support from the China Scholarship Council
Patterned Chlorination of Graphene: ClBO was dip-coated onto a (CSC) (201706060215).
graphene monolayer supported on a SiO2/Si wafer by immersing the Open access funding enabled and organized by Projekt DEAL.
graphene sample in a 0.035 mmol mL−1 acetone/toluene (v/v = 7/5)
solution of ClBO for 1 min and subsequent lifting. Immediately after
the lifting, a blow-dry treatment with argon was applied for assisting the
film formation. Afterward, the graphene sample with a layer of ClBO was Conflict of Interest
subjected to the laser writing experiments. fG-Cl with a triangle pattern The authors declare no conflict of interest.
was prepared by laser writing using a green laser (532 nm, 1.5 mW, 100×
objective, 200 s, 0.5 µm step size) and subsequent washing with acetone
as well as drying with argon.
Patterned Hydroxylation of Graphene: HOBO was spin-coated onto Data Availability Statement
a graphene monolayer supported on a SiO2/Si wafer (0.20 mmol mL−1
acetone solution of HOBO, 4000 rpm, 1 min). Afterward, the graphene The data that support the findings of this study are available from the
sample with a layer of HOBO was subjected to the laser writing corresponding author upon reasonable request.
experiments. fG-OH with a quadrangle pattern was prepared by laser
writing using a green laser (532 nm, 8 mW, 100× objective, 270 s, 0.5 µm
step size) and subsequent washing with acetone as well as drying with Keywords
argon.
Patterned Trifluoromethylation of Graphene: MFBO was dip-coated chlorination, graphene patterning, hydroxylation, hypervalent iodine
onto a graphene monolayer supported on a SiO2/Si wafer by immersing compounds, trifluoromethylation
the graphene sample in a 0.27 mmol mL−1 dichloromethane solution
of MFBO for 1 s and subsequent lifting. Immediately after the lifting, Received: February 28, 2021
a blow-dry treatment with argon was applied for assisting the film Revised: March 30, 2021
formation. Afterward, the graphene sample with a layer of MFBO was Published online: June 26, 2021
Adv. Mater. 2021, 33, 2101653 2101653 (8 of 9) © 2021 The Authors. Advanced Materials published by Wiley-VCH GmbHwww.advancedsciencenews.com www.advmat.de
[1] G. Bottari, M. Á. Herranz, L. Wibmer, M. Volland, L. Rodríguez-Pérez, [20] T. Wei, M. Kohring, H. B. Weber, F. Hauke, A. Hirsch, Nat. Commun.
D. M. Guldi, A. Hirsch, N. Martín, F. D'Souza, T. Torres, Chem. Soc. 2021, 12, 552.
Rev. 2017, 46, 4464. [21] L. Bao, B. Zhao, V. Lloret, M. Halik, F. Hauke, A. Hirsch, Angew.
[2] Y. Zhu, S. Murali, W. Cai, X. Li, J. W. Suk, J. R. Potts, R. S. Ruoff, Adv. Chem., Int. Ed. 2020, 59, 6700.
Mater. 2010, 22, 3906. [22] H. Liu, S. Ryu, Z. Chen, M. L. Steigerwald, C. Nuckolls, L. E. Brus,
[3] C. K. Chua, M. Pumera, Chem. Soc. Rev. 2013, 42, 3222. J. Am. Chem. Soc. 2009, 131, 17099.
[4] V. Georgakilas, M. Otyepka, A. B. Bourlinos, V. Chandra, N. Kim, [23] T. Wei, S. Al-Fogra, F. Hauke, A. Hirsch, J. Am. Chem. Soc. 2020,
K. C. Kemp, P. Hobza, R. Zboril, K. S. Kim, Chem. Rev. 2012, 112, 6156. 142, 21926.
[5] Y. Yang, C. Han, B. Jiang, J. Iocozzia, C. He, D. Shi, T. Jiang, Z. Lin, [24] L. G. Cançado, A. Jorio, E. H. M. Ferreira, F. Stavale, C. A. Achete,
Mater. Sci. Eng., R 2016, 102, 1. R. B. Capaz, M. V. O. Moutinho, A. Lombardo, T. S. Kulmala,
[6] M. He, J. Jung, F. Qiu, Z. Lin, J. Mater. Chem. 2012, 22, 24254. A. C. Ferrari, Nano Lett. 2011, 11, 3190.
[7] S. H. Kang, W. S. Hwang, Z. Lin, S. H. Kwon, S. W. Hong, Nano [25] P. Sessi, J. R. Guest, M. Bode, N. P. Guisinger, Nano Lett. 2009, 9,
Lett. 2015, 15, 7913. 4343.
[8] W. H. Lee, J. W. Suk, H. Chou, J. Lee, Y. Hao, Y. Wu, R. Piner, [26] V. Matoušek, E. Pietrasiak, R. Schwenk, A. Togni, J. Org. Chem.
D. Akinwande, K. S. Kim, R. S. Ruoff, Nano Lett. 2012, 12, 2374. 2013, 78, 6763.
[9] D. Ye, S.-Q. Wu, Y. Yu, L. Liu, X.-P. Lu, Y. Wu, Appl. Phys. Lett. 2014, [27] L. Zhou, L. Zhou, X. Wang, J. Yu, M. Yang, J. Wang, H. Peng, Z. Liu,
104, 103105. APL Mater. 2014, 2, 092505.
[10] K. F. Edelthalhammer, D. Dasler, L. Jurkiewicz, T. Nagel, S. Al-Fogra, [28] X. Sun, B. Li, M. Lu, J. Solid State Chem. 2017, 251, 194.
F. Hauke, A. Hirsch, Angew. Chem., Int. Ed. 2020, 59, 23329. [29] K. Amsharov, D. I. Sharapa, O. A. Vasilyev, M. Oliver, F. Hauke,
[11] L. Bao, M. Kohring, H. B. Weber, F. Hauke, A. Hirsch, J. Am. Chem. A. Goerling, H. Soni, A. Hirsch, Carbon 2020, 158, 435.
Soc. 2020, 142, 16016. [30] K. C. Knirsch, R. A. Schäfer, F. Hauke, A. Hirsch, Angew. Chem., Int.
[12] F. M. Koehler, N. A. Luechinger, D. Ziegler, E. K. Athanassiou, Ed. 2016, 55, 5861.
R. N. Grass, A. Rossi, C. Hierold, A. Stemmer, W. J. Stark, Angew. [31] Q. H. Wang, Z. Jin, K. K. Kim, A. J. Hilmer, G. L. C. Paulus,
Chem., Int. Ed. 2009, 48, 224. C.-J. Shih, M.-H. Ham, J. D. Sanchez-Yamagishi, K. Watanabe,
[13] Z. Sun, C. L. Pint, D. C. Marcano, C. Zhang, J. Yao, G. Ruan, Z. Yan, T. Taniguchi, J. Kong, P. Jarillo-Herrero, M. S. Strano, Nat. Chem.
Y. Zhu, R. H. Hauge, J. M. Tour, Nat. Commun. 2011, 2, 559. 2012, 4, 724.
[14] J. Li, M. Li, L.-L. Zhou, S.-Y. Lang, H.-Y. Lu, D. Wang, C.-F. Chen, [32] Z. Sun, Z. Yan, J. Yao, E. Beitler, Y. Zhu, J. M. Tour, Nature 2010, 468,
L.-J. Wan, J. Am. Chem. Soc. 2016, 138, 7448. 549.
[15] T. Wei, M. Kohring, M. Chen, S. Yang, H. B. Weber, F. Hauke, [33] L. Zhang, J. Yu, M. Yang, Q. Xie, H. Peng, Z. Liu, Nat. Commun.
A. Hirsch, Angew. Chem., Int. Ed. 2020, 59, 5602. 2013, 4, 1443.
[16] S. Bian, A. M. Scott, Y. Cao, Y. Liang, S. Osuna, K. N. Houk, [34] V. Mazánek, O. Jankovský, J. Luxa, D. Sedmidubský, Z. Janoušek,
A. B. Braunschweig, J. Am. Chem. Soc. 2013, 135, 9240. F. Šembera, M. Mikulics, Z. Sofer, Nanoscale 2015, 7, 13646.
[17] Z. Xia, F. Leonardi, M. Gobbi, Y. Liu, V. Bellani, A. Liscio, A. Kovtun, [35] A. L. Balch, V. J. Catalano, J. W. Lee, M. M. Olmstead, J. Am. Chem.
R. Li, X. Feng, E. Orgiu, P. Samorì, E. Treossi, V. Palermo, ACS Nano Soc. 1992, 114, 5455.
2016, 10, 7125. [36] W. Feng, P. Long, Y. Feng, Y. Li, Adv. Sci. 2016, 3, 1500413.
[18] K. Tahara, T. Ishikawa, B. E. Hirsch, Y. Kubo, A. Brown, S. Eyley, [37] A. Das, S. Pisana, B. Chakraborty, S. Piscanec, S. K. Saha,
L. Daukiya, W. Thielemans, Z. Li, P. Walke, S. Hirose, S. Hashimoto, U. V. Waghmare, K. S. Novoselov, H. R. Krishnamurthy, A. K. Geim,
S. De Feyter, Y. Tobe, ACS Nano 2018, 12, 11520. A. C. Ferrari, A. K. Sood, Nat. Nanotechnol. 2008, 3, 210.
[19] M. Yu, C. Chen, Q. Liu, C. Mattioli, H. Sang, G. Shi, W. Huang, [38] H. H. Oh, Y.-G. Ko, H. Lu, N. Kawazoe, G. Chen, Adv. Mater. 2012,
K. Shen, Z. Li, P. Ding, P. Guan, S. Wang, Y. Sun, J. Hu, A. Gourdon, 24, 4311.
L. Kantorovich, F. Besenbacher, M. Chen, F. Song, F. Rosei, Nat. [39] X. Wang, X. Hu, N. Kawazoe, Y. Yang, G. Chen, Adv. Funct. Mater.
Chem. 2020, 12, 1035. 2016, 26, 7634.
Adv. Mater. 2021, 33, 2101653 2101653 (9 of 9) © 2021 The Authors. Advanced Materials published by Wiley-VCH GmbHYou can also read
