Interface layer DFT study of first transition series XO oxides (X = Ti, Cr, Mn, Fe, Co, Ni, Cu and Zn)

Abstract

The whole universe is governed by energy in many forms. Solar cells use light energy and convert it into electrical energy. Nowadays, most of the applications depend on electrical activities. The interface layers are critical to the efficient and high-quality operation of solar cells. Solar cells, also known as photovoltaic devices, are a prospective choice for solar energy generation because of their compelling characteristics such as environmental friendliness, low cost, and lightweight [1]. We have explored new materials to design more efficient organic or inorganic solar cells through enhancement in structural and electronic properties. In this work, a Density Functional Theory (DFT) is implemented in the Spanish Initiative for Electronic Simulations with Thousands of Atoms (SIESTA), which has been performed intending to explore the interface layer of solar cells. A theoretical study is conducted to explore the structural, electronic, magnetic and optical properties of eight different compounds of d-block oxide compounds. The first transition series of oxide compounds in 2-dimensional sheet arrangements, such as TiO, CrO, MnO, FeO, CoO, NiO, CuO, and ZnO, are explored in the fabrication of solar cells. In the magnetic properties, ZnO has 0 magnetic moments or spin polarization means there is equal number of spin-up and spin-down electrons are paired in each orbitals. However, the bandgap fluctuates from the properties of semiconductors to metals. Because the first transition series oxides exhibit essentially magnetic behaviour, they have two separate band gaps for spin-up and spin-down flucation, ranging from 0 to 1 eV and 0 to 4 eV, respectively. Among all the d-block transition series oxides, CoO has the highest optical qualities, with 4.7e+05 cm−1 absorption coefficient (α), 1.2e+05 S cm-1 conductivity (σ), and 0.125 reflectivity (ρ).