Precisely controlled shape and size of gold nanostructures by seed-mediated reduction reaction method
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Precisely controlled shape and size of gold nanostructures by seed‑mediated reduction reaction method Arati Mehere1 · Nandu B. Chaure1 Received: 22 April 2020 / Accepted: 22 July 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Here we present synthesis of different shapes and sizes of Au nanostructures using seed-mediated growth method. The effect of concentration of seed solution (SS), reducing reagent, and capping molecule are investigated. Further, the growth mechanism involved of nanoshapes is discussed. A systematic red shift in the surface plasmon resonance peak observed with the decreasing SS in NP suspension demonstrates the growth of different sizes of NPs. Two surface resonance peaks (TSPR and LSPR) exhibited in the optical spectra of NRs suspension confirms the growth of NRs. The aspect ratio of NR was found increased from 1.8 to 3.2 with increasing the contents of A gNO3. For lower pH, the fixed position of TSPR peak confirms the growth of uniform diameter of NBPs. The increased transverse and longitudinal length of Au NBPs is proposed due to the absorption of more Au(0) ions on the facets of Au seed particles. A broad absorbance pattern revealed in visible to nearinfrared region for NSR suspensions was due to the complex response from the branches and plamon response of nanostar core. The Ag + ions combine with the halide significantly influence the shape and growth of NSRs. XRD data revealed that the NRs and NBPs were preferential orientation (111) crystalline rich, whereas NSRs were not abundant in (111) and (200) facets. TEM images confirm the change in shape and size of nanostructures by changing the SS, AgNO3, HCl, and AA in the respective solutions of NPs, NRs, NBPs, and NSRs. A clear lattice fringe in HRTEM images with inter-planner distance ~ 2.27 Å corresponds to (111) Bragg reflection and dotted bright circular rings evident the good crystallinity of Au nanostructures with FCC crystal structure. The ability to produce the controlled shape and size of Au nanostructures could be beneficial for solar cell applications to enhance the absorption of electromagnetic radiation in the visible region. Keywords Au nanostructures · Seed-mediated method · Structural analysis · Seed solution · CTAB
1 Introduction Nanomaterials have been attracted considerable scientific and technological interest owing to tunable electrical and optical properties simply by changing their shape and size [1–6]. Plasmonic metal nanostructures have unique optical and optoelectronic properties with their bulk counterpart. Especially, Au nanoshapes have great scientific interest because of its unique localized surface plasmon resonance in the visible to near-inferred region of the electromagnetic wave spectrum. At particular wavelength of light, the collective oscillations of electrons on the surface of gold nanoparticles (Au NPs) results in a strong * Nandu B. Chaure [email protected] 1
Department of Physics, Savitribai Phule Pune University, (formerly University of Pune), Pune
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