Nanosheet
A nanosheet is a two-dimensional nanostructure with thickness in a scale ranging from 1 to 100 nm.[1][2][3]
A typical example of a nanosheet is graphene, the thinnest two-dimensional material (0.34 nm) in the world.[4] It consists of a single layer of carbon atoms with hexagonal lattices.
Examples and applications
[edit]As of 2017[update], silicon nanosheets are being used to prototype future generations of small (5 nm) transistors.[5]
Carbon nanosheets (from hemp) may be an alternative to graphene as electrodes in supercapacitors.[6]
Synthesis
[edit]
The most commonly used nanosheet synthesis methods use a bottom-up approach, e.g., pre-organization and polymerization at interfaces like Langmuir–Blodgett films,[8] solution phase synthesis and chemical vapor deposition (CVD).[9] For example, CdTe (cadmium telluride) nanosheets could be synthesized by precipitating and aging CdTe nanoparticles in deionized water.[10] The formation of free-floating CdTe nanosheets was due to directional hydrophobic attraction and anisotropic electrostatic interactions caused by dipole moment and small positive charges. Molecular simulations through a coarse-grained model with parameters from semi-empirical quantum mechanics calculations can be used to prove the experimental process.
Ultrathin single-crystal PbS (lead sulfur) sheets with micro scale in x-, y- dimensions can be obtained using a hot colloidal synthesis method.[11] Compounds with linear chloroalkanes like 1,2-dichloroethane containing chlorine were used during the formation of PbS sheets. PbS ultrathin sheets probably resulted from the oriented attachment of the PbS nanoparticles in a two-dimensional fashion. The highly reactive facets were preferentially consumed in the growth process that led to the sheet-like PbS crystal growth.
Nanosheets can also be prepared at room temperature. For instance, hexagonal PbO (lead oxide)) nanosheets were synthesized using gold nanoparticles as seeds under room temperature.[3] The size of the PbO nanosheet can be tuned by gold NPs and Pb2+
concentration in the growth solution. No organic surfactants were employed in the synthesis process. Oriented attachment, in which the sheets form by aggregation of small nanoparticles that each has a net dipole moment,[12][13] and ostwald ripening[14] are the two main reasons for the formation of the PbO nanosheets. The same process was observed for iron sulfide nanoparticles.[15]
Carbon nanosheets have been produced using industrial hemp bast fibres with a technique that involves heating the fibres at over 350F (180C) for 24 hours. The result is then subjected to intense heat causing the fibers to exfoliate into a carbon nanosheet. This has been used to create an electrode for a supercapacitor with electrochemical qualities ‘on a par with’ devices made using graphene.[6]
Metal nanosheets have also been synthesized from solution-based method by reducing metal precursors, including palladium,[16] rhodium,[17] and gold.[18]
See also
[edit]
References
[edit]- ^ Coleman, J. N.; Lotya, M.; O'Neill, A.; Bergin, S. D.; King, P. J.; Khan, U.; Young, K.; Gaucher, A.; et al. (2011). "Two-Dimensional Nanosheets Produced by Liquid Exfoliation of Layered Materials". Science. 331 (6017): 568–571. Bibcode:2011Sci...331..568C. doi:10.1126/science.1194975. hdl:2262/66458. PMID 21292974.
- ^ Guo, Shaojun; Dong, Shaojun (2011). "Graphene nanosheet: synthesis, molecular engineering, thin film, hybrids, and energy and analytical applications". Chemical Society Reviews. 40 (5): 2644–2672. doi:10.1039/C0CS00079E. PMID 21283849.
- ^ a b Zeng, Shuwen; Liang, Yennan; Lu, Haifei; Wang, Libo; Dinh, Xuan-Quyen; Yu, Xia; Ho, Ho-Pui; Hu, Xiao; Yong, Ken-Tye (2012). "Synthesis of symmetrical hexagonal-shape PbO nanosheets using gold nanoparticles". Materials Letters. 67: 74–77. doi:10.1016/j.matlet.2011.09.048.
- ^ Geim, A. K. (2009). "Graphene: status and prospects". Science. 324 (5934): 1530–1534. arXiv:0906.3799. Bibcode:2009Sci...324.1530G. doi:10.1126/science.1158877. PMID 19541989.
- ^ IBM Figures Out How to Make 5nm Chips. June 2017
- ^ a b "Could hemp nanosheets topple graphene for making the ideal supercapacitor?". acs.org. American Chemistry Society. Retrieved 14 August 2014.
- ^ Yin, Xi; Liu, Xinhong; Pan, Yung-Tin; Walsh, Kathleen A.; Yang, Hong (November 4, 2014). "Hanoi Tower-like Multilayered Ultrathin Palladium Nanosheets". Nano Letters. 14 (12): 7188–94. Bibcode:2014NanoL..14.7188Y. doi:10.1021/nl503879a. PMID 25369350.
- ^ Payamyar, P.; Kaja, K.; Ruiz-Vargas, C.; Stemmer, A.; Murray, D. J; Johnson, C. J; King, B. T.; Schiffmann, F.; VandeVondele, J.; Renn, A.; Götzinger, S.; Ceroni, P.; Schütz, A.; Lee, L.-T.; Zheng, Z.; Sakamoto, J.; Schlüter, A. D. (2014). "Synthesis of a Covalent Monolayer Sheet by Photochemical Anthracene Dimerization at the Air/Water Interface and its Mechanical Characterization by AFM Indentation". Adv. Mater. 26 (13): 2052–2058. doi:10.1002/adma.201304705. PMID 24347495.
- ^ Sreekanth, Kandammathe Valiyaveedu; Zeng, Shuwen; Shang, Jingzhi; Yong, Ken-Tye; Yu, Ting (2012). "Excitation of surface electromagnetic waves in a graphene-based Bragg grating". Scientific Reports. 2: 737. Bibcode:2012NatSR...2E.737S. doi:10.1038/srep00737. PMC 3471096. PMID 23071901.
- ^ Tang, Z.; Zhang, Z.; Wang, Y.; Glotzer, S. C.; Kotov, N. A. (2006). "Self-assembly of CdTe nanocrystals into free-floating sheets". Science. 314 (5797): 274–278. Bibcode:2006Sci...314..274T. doi:10.1126/science.1128045. PMID 17038616.
- ^ Schliehe, C.; Juarez, B. H.; Pelletier, M.; Jander, S.; Greshnykh, D.; Nagel, M.; Meyer, A.; Foerster, S.; et al. (2010). "Ultrathin PbS sheets by two-dimensional oriented attachment". Science. 329 (5991): 550–553. arXiv:1103.2920. Bibcode:2010Sci...329..550S. doi:10.1126/science.1188035. PMID 20671184.
- ^ Talapin, Dmitri V.; Shevchenko, Elena V.; Murray, Christopher B.; Titov, Alexey V.; Král, Petr (2007). "Dipole-dipole interactions in nanoparticle superlattices". Nano Letters. 7 (5): 1213–1219. Bibcode:2007NanoL...7.1213T. doi:10.1021/nl070058c. PMID 17397231.
- ^ Tang, Z.; Zhang, Z.; Wang, Y.; Glotzer, S. C.; Kotov, N. A. (13 October 2006). "Self-Assembly of CdTe Nanocrystals into Free-Floating Sheets". Science. 314 (5797): 274–278. Bibcode:2006Sci...314..274T. doi:10.1126/science.1128045. PMID 17038616.
- ^ Yang, Weiyou; Gao, Fengmei; Wei, Guodong; An, Linan (2010). "Ostwald Ripening Growth of Silicon Nitride Nanoplates". Crystal Growth & Design. 10: 29–31. doi:10.1021/cg901148q.
- ^ Bai, Yongxiao; Yeom, Jihyeon; Yang, Ming; Cha, Sang-Ho; Sun, Kai; Kotov, Nicholas A. (2013-02-14). "Universal Synthesis of Single-Phase Pyrite FeS2 Nanoparticles, Nanowires, and Nanosheets". The Journal of Physical Chemistry C. 117 (6): 2567–2573. doi:10.1021/jp3111106. ISSN 1932-7447.
- ^ Yin, Xi; Liu, Xinhong; Pan, Yung-Tin; Walsh, Kathleen; Yang, Hong (November 4, 2014). "Hanoi Tower-like Multilayered Ultrathin Palladium Nanosheets". Nano Letters. 14 (12): 7188–94. Bibcode:2014NanoL..14.7188Y. doi:10.1021/nl503879a. PMID 25369350.
- ^ Duan, H; Yan, N; Yu, R; Chang, CR; Zhou, G; Hu, HS; Rong, H; Niu, Z; Mao, J; Asakura, H; Tanaka, T; Dyson, PJ; Li, J; Li, Y (2014). "Ultrathin rhodium nanosheets". Nature Communications. 5: 3093. Bibcode:2014NatCo...5.3093D. doi:10.1038/ncomms4093. PMID 24435210.
- ^ Li, Zhonghao; Liu, Zhimin; Zhang, Jianling; Han, Buxing; Du, Jimin; Gao, Yanan; Jiang, Tao (2005). "Synthesis of Single-Crystal Gold Nanosheets of Large Size in Ionic Liquids". The Journal of Physical Chemistry B. 109 (30): 14445–14448. doi:10.1021/jp0520998. PMID 16852818.