Raman spectroscopy study of CdS nanorods and strain induced by the adsorption of 4-mercaptobenzoic acid

Prakash, O and Umapathy, S (2023) Raman spectroscopy study of CdS nanorods and strain induced by the adsorption of 4-mercaptobenzoic acid. In: The Journal of chemical physics, 158 (13). p. 134719.

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Abstract

In this study, near- and off-resonance Raman spectra of cadmium sulfide (CdS) quantum rods (NRs) and 4-mercaptobenzoic acid (4-MBA) adsorbed CdS NRs are reported. The envelopes of characteristic optical phonon modes in the near-resonance Raman spectrum of CdS NRs are deconvoluted by following the phonon confinement model. As compared with off-resonant Raman spectra, optical phonon modes scattering cross section is amplified significantly in near-resonance Raman spectra through the Fröhlich interaction. The Huang-Rhys factor defining the strength of the Fröhlich interaction is estimated (∼0.468). Moreover, the adsorption of different concentrations of 4-mercaptobenzoic acid (4-MBA) onto CdS NRs produces surface strain in CdS NRs originating due to surface reconstruction and consequently blue and red shifts in off-resonance (514.5 nm) Raman spectra depending on the concentration of 4-MBA. These consequences are attributed to compressive and tensile strains, respectively. Relative to bulk CdS powder as the reference, strain in CdS NRs increases with decreasing 4-MBA concentrations. In off-resonance Raman spectra of 4-MBA adsorbed CdS NRs, the full width at half maxima of phonon modes (1-LO and 2-LO) and intensity ratio I2-LO/I1-LO increase with decreasing 4-MBA concentration.

Item Type:	Journal Article
Publication:	The Journal of chemical physics
Publisher:	NLM (Medline)
Additional Information:	The copyright for this article belongs to American Institute of Physics Inc.
Keywords:	Blue shift; II-VI semiconductors; Nanorods; Phonons; Raman scattering; Red Shift; Strain
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry Division of Physical & Mathematical Sciences > Instrumentation Appiled Physics
Date Deposited:	28 May 2023 05:56
Last Modified:	28 May 2023 05:56
URI:	https://eprints.iisc.ac.in/id/eprint/81495

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