Plasmon enhanced light absorption in aluminium@Hematite core shell hybrid nanocylinders: the critical role of length

EZEQUIEL R ENCINA; EDUARDO A. CORONADO

RSC Advances

Royal Society of Chemistry

Año: 2017 vol. 7 p. 2857 - 2868

2046-2069

The light absorption as well as the near field enhancements properties of Al@a-Fe2O3 core shell hybridnanocylinders (HNs) have been systematically studied by means of Discrete Dipole Approximationsimulations. The Al@a-Fe2O3 HNs consist of a right circular cylinder Al core, wrapped by a circular sectionof an a-Fe2O3 shell, both having the same finite length L. A general and useful methodology has beenimplemented to assess separately the partial contributions to the absorption spectrum of each componentof the Al@a-Fe2O3 HN. The employed methodology can be applied not only to those HNs studied here butalso to any other nanostructure with arbitrary geometry and several components providing relevantinformation not accessible through standard spectroscopic techniques. The absorption spectra have beenemployed to calculate the absorbed photon flux f within the a-Fe2O3 shell. According to the HN size,plasmon enhanced light absorption in the a-Fe2O3 shell of the Al@a-Fe2O3 HNs is evidenced, which isattributed to a plasmon-induced energy transfer mechanism based on near field enhancements. The effectof the HN length on the absorbed photon flux f is an important issue that has not been addressed yet, asonly infinitely long HN has been considered in previous studies. It is demonstrated that the HN length L hasa crucial influence on the absorbed photon flux f, as it is the main structural parameter that allows us totune the dipole plasmon resonance of the Al core into the visible region. Furthermore, it is shown that Alcores lead to larger f values than the typical plasmonic metals Ag and Au. The results presented in thiswork point out that the HN length should be explicitly taken into account for an optimum design of coreshell hybrid cylindrical nanostructures with enhanced or improved photoactive properties.