Syntheses, Characterization And Application Of One-dimensional Fluorescent Silicon Nanorods

Silicon nanomaterials feature unique optical, electronic, mechanical properties, surface tailorability, as well as favorable biocompatiblity. Particularly, one-dimensional silicon nanostructures have been elegantly developed as new powerful tools for optoelectronic and biological application, taking advantages of their attractive properties. However, there is merely one example of fluorescent one-dimensional silicon nanomaterials, which nevertheless involves relatively complicated synthetic procedures and low quantum yield values. This work focuses on the development of microwave-assisted methods for the fabrication of fluorescent one-dimensional silicon nanorods(Si NRs), and then investigates the relationships between the one-dimensional silicon nanostructure and the optical properties. We further employ the resultant Si NRs for bioimaging studies and light-emitting diodes construction. The details are as follows:(1) We report a kind of one-dimensional fluorescent silicon nanorods with tunable lengths ranging from 100 nm to 250 nm, which can be facilely prepared through one-pot microwave synthesis in aqueous phase under mild reaction conditions(e.g., reaction temperature/time: 150 oC/60 min). Meanwhile, we characterize the samples at different reaction stage to investigate the growth process.(2) Chemical/physical properties of the resultant Si NRs are investigated in systematic manners. On the basis of which, we find that, in addition to the strong fluorescence(quantum yield value: ~15%) and negligible toxicity(cell viability of He La cells treated by the Si NRs preserves >90% at 48 h), the resultant Si NRs exhibit excitation wavelength-dependent photoluminescence(maximum emission wavelengths range from ~450 nm to ~600 nm corresponding to excitation wavelengths from 390 to 560 nm).(3) Taking advantage of these attractive merits, we employ the Si NRs as fluorescent probes for multi-color biological imaging studies. More significantly, the Si NRs are photostable, preserving strong and nearly unchanged fluorescence under 400-min high-power UV irradiation. So, we further exploit the Si NRs as a novel type of color converters for the construction of white light-emitting diodes(WLED).In summary, we present a kind of fluorescent Si NRs prepared through microwave reaction. Taking advantage of the excitation wavelength-dependent emission property and robust photostability of the prepared Si NRs, we further demonstrate the feasibility of Si NRs-based fluorescent labels for multicolor bioimaging and Si NRs-based color converters for the construction of WLED. Therefore, these results raise exciting opportunities for designing one-dimensional fluorescent silicon nanostructures, and facilitate promotion of one-dimensional silicon nanomaterials-based optical applications.