Revealing the impact of aluminum doping on opto-electronic properties of CuGaSe2 thin films flexible solar cells - A DFT study

The current research work presents the impact of aluminum insertion on the material properties such as its structure, opto-electronic behavior of thin film CuGaSe2. All the calculations are performed by using density functional theory (DFT) based on the Full Potential Linear Augmented Plane Wave Method (FP-LAPW). The structural, electronic and optical properties are investigated by using the Tran-Blaha Modified Becke-Johnson potential approximation (TB-mBJ) in order to yield most accurate results. Thin film CuGaSe2 is constructed by a 2×2×2 dimensional supercell in which a vacuum of 10 Å is inserted. In this supercell 11.11% of aluminum is doped at gallium site in order to increase its band gap. Electronic properties are investigated by the energy band structure, total and partial density of state (DOS) spectra. The obtained value of energy band gap of pure CuGaSe2 is 1.17 eV and with doping it increases up to 1.27 eV. Through the absorption spectra it is proved that absorption for the solar radiation is also increases with the insertion of aluminum. The obtained results signify that the thin film of aluminum doped CuGaSe2 can be utilized in flexible solar cell applications.