We report a phosphine-free synthesis of p-type copper(I) selenide nanocrystals by a colloidal approach in a mixture of oleylamine and 1-octadecene. The nanocrystals had a cuboctahedral shape and cubic berzelianite phase. Films of these nonstoichiometric copper-deficient Cu2−xSe nanocrystals were highly conductive and showed high absorption coefficient in the near-infrared region. These nanocrystals could be used as hole-injection layers in optoelectronic devices.

Phosphine-free synthesis of p-type copper(I) selenide nanocrystals in hot coordinating solvents.

A novel method has been developed for the preparation of crystalline nanotubes of copper selenide (CuSe). The method was based on template-directed synthesis in which the trigonal Se nanotubes were used as a template-directed reagent. Apart from CuSe nanotubes, one-direction (1D) nanocrystallites of Cu3Se2, Cu2-xSe, and Cu2Se were also obtained by changing the atom ratio of Cu and Se in the precursors. The products were characterized by scanning electron microscopy (SEM), X-ray diffractometry (XRD), laser Raman spectrography (LRS), and X-ray photoelectron spectroscopy (XPS). On the basis of a series of experiments and characterizations, the formation mechanism of the CuSe nanotubes is discussed.

Synthesis and Characterization of Hexagonal CuSe Nanotubes by Templating against Trigonal Se Nanotubes

Copper chalcogenide nanocrystals (CuCNCs) as a type of semiconductor that can also act as efficient catalysts are rarely reported. Herein, we study water-soluble size-controlled Cu2−xSe nanocrystals (NCs), which are copper deficient and could be prepared by a redox reaction with the assistance of surfactants. We found them to have strong near-infrared localized surface plasmon resonance (LSPR) properties originating from the holes in the valence band, and also catalytic activity of more than a 500-fold enhancement of chemiluminescence (CL) in a luminol–H2O2 system. Investigations into the mechanisms behind these results showed that the high concentration of free carriers in Cu2−xSe NCs, which are derived from their high copper deficiencies that make Cu2−xSe NCs both good electron donors and acceptors with high ionic mobility, could greatly enhance the catalytic ability of Cu2−xSe NCs to facilitate electron-transfer processes and the decomposition of H2O2 into OH˙ and O2˙−, which are the commonly accepted key intermediates in luminol CL enhancement. Thus, it can be concluded that controllable copper deficiencies that are correlated with their near-infrared LSPR are critically responsible for the effective catalysis of Cu2−xSe NCs in the enhanced CL.

Controllable copper deficiency in Cu2−xSe nanocrystals with tunable localized surface plasmon resonance and enhanced chemiluminescence

Template free-solvothermaly synthesized copper selenide (CuSe, Cu2-xSe, β-Cu2Se and Cu2Se) hexagonal nanoplates from different precursors at low temperature

S.P. Kajve

Papers

Studies on p-type copper (I) selenide crystalline thin films for hetero-junction solar cells