For surface-enhanced fluorescence it is very important that R6G should be closed to the surface of Ag nanoparticles, this is realized under the help of PVP. However, fluorescence quenching occurred

once R6G’s immediate contact with the metal nanoparticles results in nonradiative energy transfer between the R6G and metal nanoparticles [30]. Without the strong resonance absorption at 560 nm nearby of the Ag nanosphere and the Au nanofilm, there is no fluorescence from the R6G/Ag nanosphere/PVP and R6G/Ag nanosphere/PVP/Au film. Even though the Ag nanowire/PVP has optical absorption at 560 nm nearby #BAY 1895344 manufacturer randurls[1|1|,|CHEM1|]# in Figure  3, no fluorescence in R6G/Ag nanowire/PVP is observed without Au nanofilm. Hereby, it is the

Au nanofilm that PLX3397 datasheet possesses the surface plasmon-enhanced fluorescence. The gold nanofilm is proven to be very effective fluorescence resonance energy transfer donors. The main factors that affect surface plasmon-enhanced fluorescence are (1) nanoparticle size and shape of the metal; (2) the distance between metal nanoparticles and luminophor; and (3) the electromagnetic field effect in exciting light, surface plasmon polaritons, and fluorescence of luminophor. Conclusions The absorption and fluorescence spectra of the nanocomposite PVP films with Ag nanoparticles and Rhodamine 6G prepared on the two-dimensional continuous ultrathin gold nanofilm have been studied. Absorption spectral analysis suggests that the prominently light absorption in Ag nanowire/PVP and Ag nanowire/PVP/Au film arises from the localized surface plasmons resonance of Ag nanowire and Au nanofilm. The enhanced fluorescence is observed in the presence of Ag nanowire and gold nanofilm, which is attributed to the excitation of surface plasmon

polaritons Fludarabine resonance of Ag nanowire and gold nanofilm. We have produced a two-dimensional continuous ultrathin gold nanofilm which possesses high local-field enhancement effect, high SERS activity, and surface-enhanced fluorescence. Acknowledgements This work is supported by NSFC under grant number 61307066, Doctoral Fund of Ministry of Education of China under grant numbers 20110092110016 and 20130092120024, Natural Science Foundation of Jiangsu Province under grant number BK20130630, the National Basic Research Program of China (973 Program) under grant number 2011CB302004, and the Foundation of Key Laboratory of Micro-Inertial Instrument and Advanced Navigation Technology, Ministry of Education, China under grant number 201204. References 1. Long MC, Jiang JJ, Li Y, Cao RQ, Zhang LY, Cai WM: Effect of gold nanoparticles on the photocatalytic and photoelectrochemical performance of Au modified BiVO 4 . Micro Nano Lett 2011,3(3):171–177. 2. 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.