The p–n transformation and thermoelectric property optimization of Cu_1+xFeSe₂ (x = 0–0.05) alloys

Abstract

CuFeSe2 alloys, containing earth-abundant and eco-friendly elements, are considered as environmentally friendly thermoelectric materials.

Growth of millimeter-sized high-quality CuFeSe2 single crystals by the molten salt method and study of their semiconducting behavior

“…Fig. 4 (a-b) shows the temperature dependence of resistivity and conductivity which reveals a semiconducting behavior in agreement with the results on CuFeSe 2 thin films or nanocrystals [2,19] instead of a metalic character in CuFeSe 2 bulk sample [15]. The differences in magnetic and electrical properties on various CuFeSe 2 samples synthesized via different preparation process is probably due to size effects, surface effects, interparticle interactions or impurities inside the previous sample.…”

“…There are still some controversies about the physical properties of CuFeSe 2 . Bulk eskebornite CuFeSe 2 presents a metallic character and a magnetically ordered phase below T C = 70 K [15][16][17][18] whereas serveal reports on CuFeSe 2 film and nanocrystals reveal a semiconducting behavior [2,19]. Mössbauer absorption measurements indicate a ground state of spin-density waves (SDW) nature in CuFeSe 2 [20] whereas powder neutron scattering and hysteresis loop demonstrate a weak ferrimagnetic behavior [10,18,21,22].…”

“…Recently, CuFeSe 2 has drawn considerable attention due to its promising applications in thermoelectric technology [1][2][3][4], cancer phototherapy [5][6][7][8], energy storage systems [9], optoelectronics and solar energy conversion [10][11][12][13] as well as their natural abundance, low cost, environmentally friendly nature. It crystalizes in a tetragonal phase with space group P 4 2c and lattice parameters a = b = 5.53 Å and c = 11.049 Å, which is a superstructure based upon a cubic close-packed array of anions with the cations occupying a fraction of the available tetrahedral sites as shown in Fig.…”

High-Throughput Screening for Thermoelectric Semiconductors with Desired Conduction Types by Energy Positions of Band Edges

“…For example, Cu 5 FeS 4 26 is n-type below 500 K, but it is p-type above 500 K. A similar case was also reported for CuFeSe 2 . 45 Likewise, the conduction type of CuInSe 2 and CuInS 2 are dependent on the fabrication methods. 32,33 This indicates that the ΔH(M + ) of electron donors in these compounds might be comparable with the ΔH(M − ) of electron acceptors.…”

“…(b) Summary of the energy position of conduction band minimum (ε CBM ) and band gap of 407 Cu-containing metal chalcogenides in the MatHub-3d database. (c) ε CBM and band gap of Cu-containing metal chalcogenides listed in (b) with known conduction type. − ,− The data of CuIn 5 Se 8 are obtained based on the tetragonal structure, and thus they are labeled by “t-CuIn 5 Se 8 ”.…”