Surface Modification of CdS Colloids with Mercaptoethylamine

Abstract

Abstract. Surface modification as well as size control ofCdS colloids in acetonitrile has been achieved with mercaptoethylamine (MEA). The CdS emission yield increases as it interacts with the surface modifier. A decrease in the hole-trapping yield was observed in optically excited CdS colloids wbich were modified with MEA. Use of such surface modifiers in bridging a semiconductor colloid with a gold colloid has also been demonstrated.

Photoinduced transformations in semiconductor­metal nanocomposite assemblies

“…Both emission and transient absorption spectroscopy tools are convenient to probe the electron transfer between photoexcited semiconductor and metal nanostructures (Scheme 3) [21,53]. The transient absorption spectrum recorded following 355-nm laser pulse excitation of Au/CdS colloids shows two distinct transient bleaching maxima at 480 and 545 nm, which correspond to the CdS shell and Au core, respectively.…”

“…Composite semiconductor systems have also been shown to improve the photoconversion efficiency of dye-sensitized photochemical solar cells [10,11] and photocatalytic reactions [12][13][14][15]. For more than two decades, a number of research groups have been involved in modifying the photocatalytic properties of TiO 2 and other semiconductor materials using metal deposits [16][17][18][19][20][21][22][23].…”

Optical Properties of Semiconductor Nanomaterials

“…In reality, there are impurities, defects or 120 Optical Properties and Spectroscopy of Nanomaterials The dotted vertical arrow indicates electronic transition that is not allowed by electrical dipole but can be allowed with phonon assistance. The band structure is plotted in terms of energy as a function of wave vector k = 2π/λ, namely reciprocal or momentum space (p = hk).…”

Optical and Dynamic Properties of Undoped and Doped Semiconductor Nanostructures

“…For example, TOPO (tri-n-octylphosphine oxide) capped CdSe show mostly bandedge emission and weak trap state emission, which is an indication of a high quality sample [8,79,80]. Luminescence can also be enhanced by surface modification [81][82][83][84][85][86] or using core/shell structures [12,[87][88][89]. Many nanoparticles, including CdSe, CdS, ZnS, have been found to show strong photoluminescence [90].…”

“…Luminescence usually increases at lower temperature due to suppression of electronphonon interactions and thereby increases the excited electronic state lifetime. Controlling the surface by removing surface trap states can lead to significant enhancement of luminescence as well as of the ratio of bandedge over trap state emission [81][82][83][84][85][86]. Surface modification often involves capping the particle surface with organic, inorganic, biological molecules, or even ions that reduce the amount of trap states that quench luminescence.…”