???????Structure, electronic and optical properties of chalcopyrite-type semiconducting materials XGaY2 (X = Cu, Ag, Au; Y = S, Se, Te) for solar cell applications: A DFT study

Due to a large scale demand of optoelectronics and photovoltaics devices, the study of chalcopyrite-type semi-conducting materials has emerged as one of the significant domains for research. In this report, structure and physico-chemical properties of XGaY2 (X = Cu, Ag, Au; Y= S, Se, Te) are examined in terms of Density Functional Theory technique. The energy differences between the Highest Occupied Molecular orbital (HOMO) and the Lowest Unoccupied Molecular Orbital (LUMO) of these chalcopyrite-type materials range from 2.363 eV to 3.134 eV. The compound AuGaS2 with the maximum energy gap is observed as the most stable system. Chalcopyrite materials with low HOMO-LUMO gap have the highest refractive indices and dielectric constants. Similarly, materials having high HOMO-LUMO gap display a high optical electronegativity, vibrational frequency, infrared and Raman spectra. It is observed that HOMO-LUMO gap, optical electronegativity, vibrational frequency, infrared and Raman spectra gradually decrease from sulphur to selenium to tellurium.

Automated summary

This report utilizes Density Functional Theory technique to investigate the structure and physico-chemical properties of XGaY2 (X = Cu, Ag, Au; Y= S, Se, Te), which are chalcopyrite-type semi-conducting materials. Results show that AuGaS2 is the most stable system and materials with low HOMO-LUMO gap have higher refractive indices and dielectric constants. The HOMO-LUMO gap, optical electronegativity, vibrational frequency, infrared and Raman spectra decrease gradually from sulphur to selenium to tellurium.