LAUSR

Abstract The electromagnetic enhancement mechanism of deep ultraviolet surface-enhanced fluorescence (DUV-SEF) was systematically studied theoretically for a molecule placed at the center of the aluminum (Al) nanospheres dimer. The enhanced local excitation field, fluorescence quantum yield and corresponding fluorescence enhancement were calculated in detail with finite element method (FEM). The simulation results reveal that Al nanospheres dimer can provide the strong hotspot for SEF detection in the DUV region. The excitation filed enhancement, quantum yield and fluorescence enhancement are sensitive to the dimer distance at the nanogap of two nanospheres. It was found that the stronger excitation filed enhancement with a small Al to Al distance can significantly compensate the decrease to the quantum yield, and thus lead to the larger fluorescence enhancement at smaller distance. The maximum fluorescence enhancement factor can reach as high as 4 orders at the distance of 1 nm under the excitation wavelength of 200 nm. Our studies can improve the understanding of underlying enhancement mechanism in DUV-SEF effect and further expand its applications in the DUV region.