DFT investigation of the structural, optoelectronic, thermoelectric, and thermodynamic properties of metal phosphides MP₂ (M = Co, Rh, and Ir)

Materials science is concerned with the development of novel materials that possess specified physical characteristics. In this work, we study MP 2 (M = Co, Rh, Ir) compounds which crystallize in the monoclinic structure with formation energy equal to −11.72[Formula: see text]eV, −11.62[Formula: see text]eV, and −11.13[Formula: see text]eV for CoP 2 , RhP 2 , and IrP 2 , respectively. These materials in high temperature present an important advance for thermoelectric applications. First-principles calculations with density functional theory (DFT) are employed to investigate the electrical, optical, thermoelectric, and thermodynamic properties of MP 2 (M = Co, Rh, and Ir) compounds. All computations are performed using DFT and the WIEN2k method. By combining the modified Becke–Johnson of Tran-Blaha potential (TB-mBJ) with the approximated gradient généralisé (GGA), the precision of the restricted band has been optimized. This approach, in conjunction with tools like GIBBS2 and Boltzmann’s theory of transport, has made it possible to ascertain the thermodynamic and thermoelectric properties of the materials under study. The results show that these materials have a straight band gap of CoP 2 is 4.78[Formula: see text]eV, whereas the indirect band gaps of RhP 2 and IrP 2 are 0.575[Formula: see text]eV and 0.875[Formula: see text]eV, respectively. The optical characteristics indicated good optical absorption and conductivity in the ultraviolet and visible ranges. Furthermore, using Boltzmann’s theory, it was revealed that the figure of merit ZT is more than 1.7 at a temperature of [Formula: see text][Formula: see text]K, notably for CoP2. In fact, our study demonstrates that MP2 (M = Co, Rh, and Ir) compounds might be effective in ultraviolet and visible photoelectric applications, as well as thermoelectric applications.