Jump to main content
Jump to site search

Issue 10, 2017
Previous Article Next Article

Shape and size dependent nonlinear refraction and absorption in citrate-stabilized, near-IR plasmonic silver nanopyramids

Author affiliations

Abstract

Using a combination of a mild stabilizer and a mild reductant, sodium citrate and hydrazine hydrate, anisotropic silver nanocrystals (NCs) were synthesized with tunable plasmon peaks at 550 nm, 700 nm, 800 nm, 900 nm and 1010 nm (the samples are named Ag-550, Ag-700, Ag-800, Ag-900 and Ag-1010, respectively). TEM investigations revealed that Ag-550 NCs were pentagonal nanoplates while the other four samples were nanopyramids with a pentagonal base with the edge length varying between 15 and 30 nm. The non-linear optical (NLO) properties of these NCs were studied by the Z-scan technique using the CW He–Ne laser (632.8 nm, 15 mW). The shape change from 2D nanoplates (Ag-550) to 3D nanopyramids (Ag-700) resulted in sign reversal of the non-linear refractive index, n2, from a negative (−3.164 × 10−8 cm2 W−1) to a positive one (1.195 × 10−8 cm2 W−1). This corresponds to a change from a self-defocussing effect to a self-focussing one. Besides shape, the size effect is also prominently observed. Amongst nanopyramids, as the edge length increases, n2 increases linearly and reaches a maximum of 3.124 × 10−8 cm2 W−1. Doubling the edge length from 15 nm to 30 nm resulted in 162% increase in n2. On moving from Ag-550 to Ag-900 NCs, with the increasing plasmon wavelength, the non-linear absorption (NLA) coefficient increased exponentially to a high value of 8.52 × 10−4 cm W−1. However, Ag-1010 showed 29% decrease in NLA which is attributed to twinning present in the crystal structure as seen in the HR-TEM images. Due to the tunable NLO properties, these anisotropic Ag NCs hold great potential for applications in optical limiting, switching and data storage.

Graphical abstract: Shape and size dependent nonlinear refraction and absorption in citrate-stabilized, near-IR plasmonic silver nanopyramids

Back to tab navigation

Supplementary files

Publication details

The article was received on 07 Jul 2017, accepted on 18 Aug 2017 and first published on 18 Aug 2017


Article type: Paper
DOI: 10.1039/C7PP00257B
Citation: Photochem. Photobiol. Sci., 2017,16, 1556-1562
  •   Request permissions

    Shape and size dependent nonlinear refraction and absorption in citrate-stabilized, near-IR plasmonic silver nanopyramids

    B. K. Dadhich, I. Kumar, R. K. Choubey, B. Bhushan and A. Priyam, Photochem. Photobiol. Sci., 2017, 16, 1556
    DOI: 10.1039/C7PP00257B

Search articles by author

Spotlight

Advertisements