[1] [1] Zeng J H, Su J, Li Z H, et al. Synthesis and upconversion luminescence of hexagonal-phase NaYF4∶Yb, Er3+ phosphors of controlled size and morphology［J］. Advanced Materials, 2005, 17(17): 2119-2123.

[2] [2] Ye Shuai, Song Jun, Chen Linchun, et al. Research on photoluminescence of Nd3+ doped NaYF4∶Yb, Er/Tm upconversion nanoparticles［J］. Acta Optica Sinica, 2015, 35(8): 0816005.

[3] [3] Wang F, Liu X G. Recent advances in the chemistry of lanthanide-doped upconversion nanocrystals［J］. Chemical Society Reviews, 2009, 38(4): 976-989.

[4] [4] Zhou J, Liu Q, Feng W, et al. Upconversion luminescent materials: Advances and applications［J］. Chemical Reviews, 2015, 115(1): 395-465.

[5] [5] Huang X R, Han S Y, Huang W, et al. Enhancing solar cell efficiency: The search for luminescent materials as spectral converters［J］. Chemical Society Reviews, 2013, 42(1): 173-201.

[6] [6] Li C X, Yang D M, Ma P G, et al. Multifunctional upconversion mesoporous silica nanostructures for dual modal imaging and in vivo drug delivery［J］. Small, 2013, 9(24): 4150-4159.

[7] [7] Chen G Y, Qiu H L, Prasad P N, et al. Upconversion nanoparticles: Design, nanochemistry, and applications in theranostics［J］. Chemical Reviews, 2014, 114(10): 5161-5214.

[8] [8] Liu X F, Dong G P, Qiao Y B, et al. Transparent colloid containing upconverting nanocrystals: An alternative medium for three-dimensional volumetric display［J］. Applied Optics, 2008, 47(34): 6416-6421.

[9] [9] Saboktakin M, Ye X, Oh S J, et al. Metal-enhanced upconversion luminescence tunable through metal nanoparticle-nanophosphor separation［J］. ACS Nano, 2012, 6(10): 8758-8766.

[10] [10] Yin Z, Zhou D L, Xu W, et al. Plasmon-enhanced upconversion luminescence on vertically aligned gold nanorod monolayer supercrystals［J］. ACS Applied Materials & Interfaces, 2016, 8(18): 11667-11674.

[11] [11] Lu D W, Cho S K, Ahn S, et al. Plasmon enhancement mechanism for the upconversion processes in NaYF4∶Yb3+, Er3+ nanoparticles: Maxwell versus Frster［J］. ACS Nano, 2014, 8(8): 7780-7792.

[12] [12] Li A H, Lü M Y, Guo L, et al. Enhanced upconversion luminescence of metal-capped NaGd0.3Yb0.7F4∶Er submicrometer particles［J］. Small, 2016, 12(15): 2092-2098.

[13] [13] Zhang H, Li Y J, Ivanov I A, et al. Plasmonic modulation of the upconversion fluorescence in NaYF4∶Yb/Tm hexaplate nanocrystals using gold nanoparticles or nanoshells［J］. Angewandte Chemie, 2010, 122(16): 2927-2930.

[14] [14] Liu J M, Liu Y Y, Zhang D D, et al. Synthesis of GdAlO3∶Mn4+, Ge4+@ Au core-shell nanoprobes with plasmon-enhanced near-infrared persistent luminescence for in vivo trimodality bioimaging［J］. ACS Applied Materials & Interfaces, 2016, 8(44): 29939-29949.

[15] [15] Chen G X, Ding C J, Wu E, et al. Tip-enhanced upconversion luminescence in Yb3+-Er3+ codoped NaYF4 nanocrystals［J］. Journal of Physical Chemistry, 2015, 119: 22604-22610.

[16] [16] Khatua S, Paulo P M R, Yuan H, et al. Resonant plasmonic enhancement of single-molecule fluorescence by individual gold nanorods［J］. ACS Nano, 2014, 8(5): 4440-4449.

[17] [17] Li Ming, Li Kaiwei, Dai Fang, et al. Highly sensitive optical nanofiber sensor based on gold nanorod amplification［J］. Acta Optica Sinica, 2015, 35(12): 1206001.

[18] [18] Greybush N J, Saboktakin M, Ye X C, et al. Plasmon-enhanced upconversion luminescence in single nanophosphor-nanorod heterodimers formed through template-assisted self-assembly［J］. ACS Nano, 2014, 8(9): 9482-9491.

[19] [19] Feng A L, You M L, Tian L M, et al. Distance-dependent plasmon-enhanced fluorescence of upconversion nanoparticles using polyelectrolyte multilayers as tunable spacers［J］. Scientific Reports, 2015, 5: 07779.

[20] [20] Ye X C, Zheng C, Chen J, et al. Using binary surfactant mixtures to simultaneously improve the dimensional tunability and monodispersity in the seeded growth of gold nanorods［J］. Nano Letters, 2013, 13(2): 765-771.

[21] [21] Palik E D. Handbook of optical constants of solids［M］. New York: Academic Press, 1984: 290-295.

[22] [22] Mock J J, Smith D R, Schultz S. Local refractive index dependence of plasmon resonance spectra from individual nanoparticles［J］. Nano Letters, 2003, 3(4): 485-491.