Localized surface plasmon enhanced photothermal conversion in Bi2Se3 topological insulator nanoflowers.

Jia Guozhi,Chang Kai,Zhang Yanbang,Wang Peng

doi:10.1038/srep25884

Abstract

Localized surface plasmons (LSP), the confined collective excitations of electrons in noble metal and doped semiconductor nanostructures, enhance greatly local electric field near the surface of the nanostructures and result in strong optical response. LSPs of ordinary massive electrons have been investigated for a long time and were used as basic ingredient of plasmonics and metamaterials. LSPs of massless Dirac electrons, which could result in novel tunable plasmonic metamaterials in the terahertz and infrared frequency regime, are relatively unexplored. Here we report for first time the observation of LSPs in Bi2Se3 topological insulator hierarchical nanoflowers, which are consisted of a large number of Bi2Se3 nanocrystals. The existence of LSPs can be demonstrated by surface enhanced Raman scattering and absorbance spectra ranging from ultraviolet to near-infrared. LSPs produce an enhanced photothermal effect stimulated by near-infrared laser. The excellent photothermal conversion effect can be ascribed to the existence of topological surface states, and provides us a new way for practical application of topological insulators in nanoscale heat source and cancer therapy.

Highlights

Will be relaxed, making it more easy to excite the collective excitation, i.e., localized surface plasmons (LSPs) in TI nanostructures
The compositions of the sample determined by energy dispersive spectroscopy (EDS) was shown in Fig. 1C, confirming the presence of Se and Bi atoms, which demonstrated that Se NCs can serve as soft templates for preparing Bi2Se3 NFs17,18
As the sizes of Bi2Se3 NCs decrease, the localized surface plasmon resonances (LSPRs) peak appear, and approach the near infrared band, which could be very promising for application of the photothermal conversion in cancer therapy. 808 nm NIR laser was delivered through a quartz cuvette containing aqueous dispersion NFs to measure the photothermal conversion performance of hydrophilic Bi2Se3 NFs

Summary

Introduction

Will be relaxed, making it more easy to excite the collective excitation, i.e., localized surface plasmons (LSPs) in TI nanostructures. The oscillation of LSP can be enhanced through resonance with the driving electromagnetic field, resulting in surface-enhanced Raman scattering, which depend on the generation of LSPs at interfaces dielectric core and noble metal shell. In contrast to this hybridized dielectric/metal nanostructures, TI nanostructures posses exotic metallic surface states, one can expect that the metallic surface states can substantially enhance local fields near the surface and affect the optical property of TI nanostructures. Utilizing enhanced local field near the surface of TI nanostructures, we find an excellent photothermal conversion in TI nanostructures, which is comparable with or even better than that in conventional semiconductor nanostructures coated with noble metal shell. Our work demonstrates the TI nanostructures could be used in nanoscale heat sources and cancer therapy, paves a completely new way toward practical applications of TIs

Methods

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Discussion

Conclusion