First-principles investigations of structural, optoelectronic and thermoelectric properties of Cu-based chalcogenides compounds

Abstract

The structural, electronic, optical and thermoelectric properties of copper-based ternary chalcogenides ACuSe 2 (A = Sc, Y and La) were investigated within the framework of the density functional theory (DFT). The electronic band structures and density of states exhibit that ScCuSe 2 and YCuSe 2 have the indirect band gaps, while LaCuSe 2 displays a direct band gap-type transition. The band structure calculations agree well with other results in the literature. The optical behavior of the studied materials was analyzed in terms of dielectric functions, refractive index, extinction coefficient, absorption coefficient, optical conductivity, reflectivity and energy loss factor. The refractive indices increase to the maximum values of 4.4, 4 and 4.1 at the short infrared and visible wavelengths for ScCuSe 2 , YCuSe 2 and LaCuSe 2 , respectively. Then, they decrease to get a value below 1.0 at the UV wavelengths. Moreover, the material response with temperature was investigated by Seebeck coefficient, figure of merit, specific heat capacity, power factor, thermal conductivity and susceptibility. The high Seebeck effect and large power factor values confirm the efficiency of these materials in thermoelectric energy converter technology. Among the three studied ternary materials, YCuSe 2 has the highest value of dimensionless figure of merit of 0.45 at room temperature. These results would probably provide a new route to the experimentalists for the potential usage and applications of ScCuSe 2 , YCuSe 2 and LaCuSe 2 in thermoelectric and optoelectronic devices.

Quaternary Selenides EuLnCuSe3: Synthesis, Structures, Properties and In Silico Studies

“…Selenides of the rhombic system EuLnCuSe 3 (Ln = La-Lu, Sc, Y) with the band gap of 0.82-1.09 eV were also predicted [32]. Quaternary selenides EuLnCuSe 3 are also indirectly predicted by the existence of tertiary selenides CuLnSe 2 [18,48,49]. The former compounds should form in the CuLnSe 2 -EuS section of the EuS-Ln 2 Se 3 -Cu 2 S ternary system analogously to the chalcogenides of a similar composition [38][39][40][41][50][51][52][53][54][55][56][57][58][59].…”

“…Nowadays, the copper-containing chalcogenides are of particular interest and in the limelight of many studies, the reason being their thermal, electrical and optical properties, which make them promising materials for infrared (IR) and nonlinear optics [1,2], photocatalysis, photoelectric energy and proton conductivity [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Development of electronic technologies opened prospects for the copper containing selenides as one of the most promising absorbers in thin film photovoltaic cells and high-performance thermoelectric materials [19,20].…”

High thermoelectric performance in XAgSe2 (X = Sc, Y) from strong quartic anharmonicity and multi-valley band structure

“…At room temperature, the zT value of n-type YAgSe 2 along the a ( b )-axis at the optimal carrier concentration was 0.65, which is better than 0.40 of YCuSe 2 . 52 Even more remarkable, both materials demonstrated outstanding TE performance at elevated temperatures. The zT values of n-type ScAgSe 2 (YAgSe 2 ) along the a ( b )-axis and p-type ScAgSe 2 (YAgSe 2 ) along the c -axis were 3.40 (3.63) and 3.49 (3.70), respectively, both exceeding that of SnSe at 923 K, which was 2.62.…”

First-Principles Investigations of Thermoelectric Behavior of RuCrX (X = Si, Ge, Sn)

“…The ability to predict structure–property relationships has revolutionized experimental fields, such as vibrational and solid-state NMR spectroscopy. In semiconductor physics, great progress has been made in the electronic structure of bulk and defect states despite the severe challenges presented by the description of excited states. , The thermoelectric parameters calculations were done by solution of Boltzmann transport equations. These calculations were carried out by using norm-conserving Troullier-Martins pseudopotentials within Perdew Burke Ernzerhof Generalized Gradient Approximations for the recovery of exchange correlation energy with plane-wave basis as implemented in Quantum ESPRESSO .…”