Zhu et al. Nanoscale Research Letters 2012, 7:613 http://www.nanoscalereslett.com/content/7/1/613 Page 6 of 7 Figure 5 SERS spectra of R6G (10−5 M) obtained from the surface of the three samples. Conclusions In summary, a rapid, simple, and room-temperature electrophoretic deposition method has been proposed to fabricate GNP thin films with high mechanical adhesion strength. Sub-10-nm gaps between neighboring particles have been formed when GNP deposition density increases. The films made by this method exhibit a high Raman signal due to the strong LSPR effect, which is produced in the narrow gap regions. This design of GNP thin films with a highly sensitive SERS-active property may provide a new framework for the fabrication of large-area SERS-based sensors. Competing interests The authors declare that they have no competing interests. Authors' contributions S-QZ carried out the design and the characterization of GNP thin films, performed the SERS analysis, and drafted the manuscript. TZ, X-LG, Q-LW, XL, and X-YZ read and contributed in the improvement of the manuscript. All authors read and approved the final manuscript. Acknowledgements This work is supported by NSFC under grant nos. 60977038 and 21173041, the Doctoral Fund of Ministry of Education of China under grant no. 20110092110016, Graduate Innovation Program of Jiangsu Province under grant no. CXLX_0114, and the National Basic Research Program of China (973 Program) under grant no. 2011CB302004. Author details 1School of Electronic Science and Engineering, Southeast University, Nanjing 210096, People's Republic of China. 2Key Laboratory of Micro-Inertial Instrument and Advanced Navigation Technology, Ministry of Education, Nanjing 210096, People's Republic of China. 3Suzhou Key Laboratory of Metal Nano-Optoelectronic Technology, Suzhou Research Institute of Southeast University, Suzhou 215123, People's Republic of China. 4School of Materials Science and Engineering, Southeast University, Nanjing 211189, People's Republic of China. 5Institute of Optics and Electronics, CAS, PO Box 350, Chengdu, Shuangliu 610209, China. Received: 3 September 2012 Accepted: 14 October 2012 Published: 6 November 2012 References 1. Alivisatos P: The use of nanocrystals in biological detection. Nat Biotechnol 2004, 22:47–52. 2. Krasteva N, Besnard I, Guse B, Bauer RE, Mullen K, Yasuda A, Vossmeyer T: Self-assembled gold nanoparticle/dendrimer composite films for vapor sensing applications. Nano Lett 2002, 2:551–555. 3. Shrivastava S, Dash D: Label-free colorimetric estimation of proteins using nanoparticles of silver. Nano-Micro Lett 2010, 2:164–168. 4. Lu X, Rycenga M, Skrabalak SE, Wiley B, Xia Y: Chemical synthesis of novel plasmonic nanoparticles. Annu Rev Phys Chem 2009, 60:167–192. 5. Wu J, Mangham SC, Reddy VR, Manasreh MO, Weaver BD: Surface plasmon enhanced intermediate band based quantum dots solar cell. Sol Energy Mater Sol Cells 2012, 102:44–49. 6. Yang J, You J, Chen CC, Hsu WC, Tan HR, Zhang XW, Hong Z, Yang Y: Plasmonic polymer tandem solar cell. ACS Nano 2011, 5:6210–6217. 7. Akimov YA, Ostrikov K, Li EP: Surface plasmon enhancement of optical absorption in thin-film silicon solar cells. Plasmonics 2009, 4:107–113. 8. Derkacs D, Chen WV, Matheu PM, Lim SH, Yu PKL, Yu ET: Nanoparticle- induced light scattering for improved performance of quantum-well solar cells. Appl Phys Lett 2008, 93:091107. 9. Campion A, Kambhampati P: Surface-enhanced Raman scattering. Chem Soc Rev 1998, 27:241–250. 10. McLellan JM, Li ZY, Siekkinen AR, Xia Y: The SERS activity of a supported Ag nanocube strongly depends on its orientation relative to laser polarization. Nano Lett 2007, 7:1013–1017. 11. Jackson JB, Halas NJ: Surface-enhanced Raman scattering on tunable plasmonic nanoparticle substrates. Proc Natl Acad Sci 2004, 101:17930–17935. 12. Yu X, Wang L, Di J: Electrochemical deposition of high density gold nanoparticles on indium/tin oxide electrode for fabrication of biosensors. J Nanosci Nanotechnol 2011, 11:11084–11088. 13. Berkovitch N, Ginzburg P, Orenstein M: Concave plasmonic particles: broad-band geometrical tunability in the near-infrared. Nano Lett 2010, 10:1405–1408. 14. Lucas D, Kim JS, Chin C, Guo LJ: Nanoimprint lithography based approach for the fabrication of large-area, uniformly-oriented plasmonic arrays. Adv Mater 2008, 20:1129–1134.