Ab-initio study of Cu-based oxychalcogenides: A new class of materials for optoelectronic applications

Abstract

The Cu-based oxychalcogenides among p-type transparent conducting materials (TCMs) demonstrate significant results in term of their optoelectronic properties. So, they are being focused on our current study. In this paper, we reported a detailed analysis relating to the spin-dependent electronic and optical properties of Cu-based Lanthanide oxychalcogenides materials, ACuOS (A ​= ​La, Ce and Pr) by means of Density Functional Theory (DFT). We observe a decrease in the energy band-gap values for the substitution of lanthanide La→Pr which was in a fine agreement to the experimental results. The band-gap energy values are concluded to be smaller for the case of spin up in comparison to spin down case. The majority and minority spin cases of the band structures and density of states for the three materials are compared and discussed in detail. We also computed spin-dependent optical parameters like the real and imaginary parts of dielectric function, refractive index, reflectivity, absorption coefficient and the electron energy loss function for radiations up to energy value of 14 ​eV. Our investigated optical parameters for these Cu-based oxychalcogenides reveals dissimilarities for both the spin up and down, which are the outcomes of the energy band-gap variations and also the existence of additional structures closer to the Fermi levels which are mostly due to the lanthanides 4f electrons. Their basic material properties including their crystal structures, optical and electronic properties will be covered, as well as their device applications. Also, the development of performance enhancement strategies including doping and other innovative ways to improve performance is still not satisfactory. This has impeded the development of many devices such as photovoltaics, sensors, and transparent electronics properties of materials.