First principles study of structural, optoelectronic and thermoelectric properties of Cu2CdSnX4 (X = S, Se, Te) chalcogenides

• Copper based quaternary chalcogenides are important for optoelectronic devices.
• The WC-GGA shows that the materials are metallic in nature.
• The EV-GGA predicts better band gaps compared to WC-GGA.
• Absorption peaks are high in the visible and ultraviolet energy regions.
• All the semiconductors have figure of merit above 0.70.

In this work, structural, electronic, optical and thermoelectric properties of Cu2CdSnX4 (X = S, Se, Te) have been studied through the full potential linearized augmented plane wave method. Calculated ground state lattice parameters are in good agreement with the experimental results. Lattice constant and bulk moduli vary inversely by replacing the anion X from S to Te in Cu2CdSnX4. The WC-GGA shows that the materials are metallic in nature. The EV-GGA predicts better band gaps compared to WC-GGA. The calculated bandgap values are 1.8, 1.06 and 0.8042 for Cu2CdSnX4, Cu2CdSnX4, Cu2CdSnX4 respectively. Cd-d, Sn-s and X-p states contribute significantly in the density of states of the compounds. Absorption peaks and optical conductivity is high in the visible and ultraviolet energy regions. All the semiconductors have figure of merit above 0.70. The optical and thermoelectric properties clearly show that Cu2CdSnX4 are potential candidates in the fields of solar cell and thermoelectric technology.

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