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Surfactant-mediated variation of band-edge emission in CdS nanocomposites.

Authors :: O’Dwyer, C.
Lavayen, V.
Mirabal, N.
Santa Ana, M.A.
Benavente, E.
Ormazabal, S.
González, G.
Lopez, Z.
Schöps, O.
Woggon, U.
Sotomayor Torres, C.M.
Source :: Photonics & Nanostructures: Fundamentals & Applications; Oct2007, Vol. 5 Issue 2/3, p45-52, 8p
Publication Year :: 2007
Abstract: Abstract: The optical–structural characteristics of the direct optical band-gap semiconducting series of surfactant template-mediated laminar (CdS)<subscript> x </subscript>(CdCl<subscript>2</subscript>)<subscript> y </subscript>(C<subscript> n </subscript>H<subscript>2n+4</subscript>N)<subscript> z </subscript> nanocomposites are reported. X-ray diffraction measurements of the nanocomposites exhibited interlaminar distances in the range 2.9–3.6 nm with observations of eighth order diffraction planes indicative of a high degree of laminarity and crystallographic order. Diffuse reflectance measurements have determined that the profile of their emission spectrum is that of a direct band-gap with absorption edges in the range 2.11–2.40 eV, depending on the CdS mole fraction in the nanocomposite. Photoluminescence (PL) excitation and time-resolved PL spectroscopies give an estimate of the maximum relative absorbance of the nanocomposites at 420 nm while the minimum was observed at 560 nm. The main emission was observed at 700 nm with emission from doubly ionized sulphur vacancies observed at 615 nm at room temperature. The CdS-containing nanocomposite is thus a surfactant-mediated modular system with variable band-gap energy emission. [Copyright &y& Elsevier]