Synthesis, characterizations, and optical properties of copper selenide quantum dots

Abstract

We demonstrate the synthesis of copper selenide quantum dots (QDs) by element directed, inexpensive, straight forward wet chemical method which is free from any surfactant or template. Copper selenide QDs have been synthesized by elemental copper and selenium in the presence of ethylene glycol, hydrazine hydrate, and a defined amount of water at 70°C within 8 h. The product is in strong quantum confinement regime, phase analysis, purity and morphology of the product has been well studied by X-ray diffraction (XRD), UV-Visible spectroscopy (UV-Vis), Photo-luminescent spectroscopy (PL), Fourier transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), High resolution transmission electron microscopy (HRTEM), and by Atomic force microscopy (AFM) techniques. The absorption and photoluminescence studies display large ''blue shift''. TEM and HRTEM analyses revealed that the QDs diameters are in the range 2-5 nm. Due to the quantum confinement effect copper selenide QDs could be potential building blocks to construct functional devices and solar cell. The possible mechanism is also discussed.

Synthesis and growth mechanism of dendritic Cu2−xSe microstructures

“…Many recent efforts have been devoted to the synthesis of copper selenides micro-and nanocrystallites with various structures and morphologies by thermolysis of single-source precursor [5], ultrasonochemical techniques [6], template-directed reaction [7,8], electrochemical crystallization process [9], hot-injection method [10] and hydrothermal routes [11][12][13]. In particular, recent works report solution strategies which allow to control the shape and the structure of the synthesized Cu 2Àx Se nanocrystals by changing the precursors in the reaction [14] or the reaction parameters [12,15].…”

Characterization of single phase copper selenide nanoparticles and their growth mechanism

“…In view of this, Kumar et al [22] and Kumar and Singh [23] have used this method to prepare different phases (CuSe, Cu 2À x Se, b-Cu 2 Se, Cu 2 Se) of copper selenide taking chloride, sulfate, nitrate etc. of copper and elemental copper as copper source with elemental selenium.…”

Two Step Hydrothermal Synthesis of Nanocrystalline CDS

“…Figure 3 shows the room temperature PL spectra of the CdS nanocrystals excited at 300 nm. The figure shows a sharp emission peak centered at 490.5 nm, which may represent the recombination of free excitons [1,18]. This puts the band gap value at slightly higher than 2.5 eV.…”

“…The small size and high surface to volume ratio of nanocrystals of inorganic compound semiconductors exhibit interesting physical, chemical and optical properties [1].CdS have two different crystal structures cubic zinc blende and hexagonal wurtzite. Cadmium sulphide is extensively used in various applications such as in non-linear devices, solar cells, display devices, x-ray detectors, in the pigments and plastic industry, and as photo-catalysts [1][2][3][4][5][6][7][8][9][10].It is well known that the properties of nanocrystals of cadmium sulphide are controlled by the growth process and different growth conditions [4].…”

“…Cadmium sulphide is extensively used in various applications such as in non-linear devices, solar cells, display devices, x-ray detectors, in the pigments and plastic industry, and as photo-catalysts [1][2][3][4][5][6][7][8][9][10].It is well known that the properties of nanocrystals of cadmium sulphide are controlled by the growth process and different growth conditions [4]. It is necessary to develop various approaches to prepare high quality nanoparticles CdS nanocrystals.…”