Title:	Nonlinear optical investigations in nine-atom silver quantum clusters and graphitic carbon Nitride Nanosheets
Authors:	Sridharan, Kishore Sreekanth, P. Park, Tae Joo Philip, Reji
Issue Date:	18-Jun-2015
Publisher:	American Chemical Society
Citation:	Journal of Physical Chemistry C, 2015. Vol 119, p16314
Abstract:	Absorption saturation due to surface plasmon resonance affects the optical limiting efficiency of metal nanoparticles (NPs) by raising the limiting threshold to higher laser fluences. It has been shown that in gold, compared to the larger NPs, smaller quantum clusters (QCs) exhibit better optical limiting with lower limiting thresholds due to the absence of absorption saturation. Here we report optical limiting properties of two novel materials, namely, nine-atom silver (Ag9) QCs and graphitic carbon nitride (GCN) nanosheets. The relatively large nonlinear absorption of Ag9 QCs compared to Ag NPs is revealed from open-aperture Z-scan measurements carried out using 532 nm, 5 ns laser pulses. Optical nonlinearity in the QCs arises mostly from free carrier absorption and a relatively weak saturable absorption. The superior limiting efficiency of Ag9 QCs is complemented by excellent chemical stability, which makes silver quantum clusters ideal candidates for optical limiting applications. The two-dimensional sheet-like structure of GCN is ideal for grafting metals and semiconductors, and we show that even though the nonlinearity of pristine GCN is low it can be improved substantially by grafting lightly with Ag9 QCs
Description:	Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations)
URI:	http://hdl.handle.net/2289/6301
ISSN:	1932-7447 1932-7455 (Online)
Alternative Location:	http://dx.doi.org/10.1021/acs.jpcc.5b02372
Copyright:	2015 American Chemical Society
Appears in Collections:	Research Papers (LAMP)

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