Hybrid Electrochemical/Chemical Synthesis of Quantum Dots

Abstract

The "electrochemical/chemical method" (or "E/C method") is a new wet chemical method for synthesizing semiconductor quantum dots on graphite surfaces. The E/C synthesis of quantum dots composed of the generic semiconducting salt, MX, typically involves three steps: (1) electrochemical deposition of nanoparticles of the metal, M°, from a solution of metal ions, M n+ ; (2) electrochemical oxidation of these metal particles to MOn/2, and; (3) displacement of the oxygen from MOn/2 using HX (for example) to yield nanoparticles of MX. This conversion from metal to metal oxide to metal salt occurs on a particle-by-particle basis; that is, each metal nanoparticle is converted into a semiconductor nanoparticle. E/C-synthesized -CuI and CdS quantum dots possess many of the attributes of quantum dots synthesized using molecular beam epitaxy, including epitaxial orientation on the graphite surface, a narrow size dispersion, and strong, particle size-tunable photoluminescence. However, the E/C method is faster, cheaper, and applicable to a greater number of materials.

Synthesis of copper quantum dots by chemical reduction method and tailoring of its band gap

“…Quantum confinement can be defined as, in nano particles whose diameter is smaller than the size of its Bohr-exciton radius the degree of freedom of particle is reduced from N to zero. [11][12][13][14][15][16] So energy levels can be modelled using particle in a box model in which the energy of different states depend on the length of the box. If there radii are on the Bohr-exciton radius, then the quantum dots are said to be in weak confinement regime and the radii less than the Bohr-exciton radius, then the quantum dots are said to be in strong confinement regime.…”

Fluorescence Quenching of CdTe Nanocrystals by Bound Gold Nanoparticles in Aqueous Solution

“…show enormous photostability over regular organic fluorophores [30][31][32][33][34]. They also display size-tunable absorption and emission properties due to quantum size effect.…”

ATP synthesis in the energy metabolism pathway: a new perspective for manipulating CdSe quantum dots biosynthesized in <em>Saccharomyces cerevisiae</em>

“…Thus, tremendous interest has arisen in the synthesis of well-dispersed and uniform-sized nanomaterials. 9,10 Nanoparticles biosynthesized by organisms, without involving the toxic solvents, strict conditions, or expensive processes that are needed in chemical methods, have become a popular subject. 11 Various nanoparticles are reported that are biosynthesized by bacteria, [12][13][14] fungi, 15,16 plants, 17,18 mammalian cells, 19 or even earthworms.…”