One-step room temperature rapid synthesis of Cu₂Se nanostructures, phase transformation, and formation of p-Cu₂Se/p-Cu₃Se₂heterojunctions

Abstract

A tetragonal Cu 2 Se film containing a well-aligned nanosheet array with scattered 3D flower-like microstructures on top was synthesized for the first time by a rapid one-step low-energy route, which is beneficial for large scale industrial production due to savings in energy, time and expensive instruments. Phase transformation occurred after scraping the film from the Cu substrate, and heating or grinding the Cu 2 Se powder in air. The Cu 2 Se/Cu 3 Se 2 composite containing p-Cu 2 Se/p-Cu 3 Se 2 heterojunctions was obtained by simply calcining the Cu 2 Se in air at 300 °C for 3 h. The composite has enhanced gas sensing properties towards acetone gas and a lower band gap energy compared to Cu 2 Se.

Enhanced Stability and Thermoelectric Performance in Cu1.85Se-Based Compounds

“…Additionally, to examine the binding states of the Li 0.03 Cu 1.81 Bi 0.04 Se sample, XPS analysis is performed, as seen in Figure S4. The fitted peaks of the Cu 2p and Se 3d spectrum (Figure S4a,b) are consistent with the literature. − Besides, Bi 4f peaks appear at 158.8, 163.4, and 164.1 eV, which can be assigned to Bi 3+ , while the presence of Li 1s peaks is in contrast to that observed in the metallic Li …”

“…Together with the reduced thermal conductivity by alloying with S, a maximum ZT of about 0.9 at 760 K is obtained for Li 0.03 Cu 1.81 Bi 0.04 Se 0.9 S 0.1 , 350% higher than that of Cu 1.85 Se. Simultaneously, incorporating the decent ZT and high V c , Cu 1.85 Se-based materials have great potential for applications in the medium- to high-temperature range. − In general, Cu 1.85 Se-based materials has been proved to be a kind of thermoelectric material with great potential.…”

Effect of Sc and Zr on Al₆(Mn,Fe) Phase in Al–Mg–Mn Alloys

“…AlMg alloys are widely used in aircrafts and ships due to their excellent tensile strength, specific gravity, elongation, and corrosion resistance. 13) Mg is the highest alloying element in AlMg alloys. Mg has the solution strengthening effect in aluminium alloys and can improve the work hardening rate of the material.…”

“…In general, iron is an common impurity in AlMg alloys and can precipitate as the Al 13 Fe 4 phase. 5,6) Al 13 Fe 4 can cut off the matrix and decrease the mechanical properties. The type, number density, and size of Fe-rich phases in the microstructure have an enormous influence on the combination properties of Al-based alloys.…”

“…1012) In the presence of Fe element, the addition of Mn can form the Al 6 (Mn,Fe) phase, which can improve the mechanical properties via precipitation and dispersion strengthening and hence, reduce the negative effects. 13) However, research has indicated that Al 6 (Mn,Fe) can act as a local cathode when compared with the matrix, which decreases the corrosion resistance of AlMg alloys. 14) Addition of Sc to Al-based alloys have significant grain refinement effect.…”