DFT based study of copper calcium halide perovskite nanomaterials for optoelectronic and energy applications

The mechanical, electronic, optical, and thermoelectric analyses of CuCaX3 (X = Cl, Br, I) have been done using DFT based TB-mBJ approach. The stability of CuCaX3 (X = Cl, Br, I) has been confirmed from the enthalpy of formation; values for CuCaCl3, CuCaBr3, and CuCaI3 are -1.07 eV, -1.55 eV, and -2.15 eV, respectively. The phonon spectra plot is also discussed, and the phonon dispersion analysis confirms that the CuCaX3 systems are dynamically stable since no imaginary modes are observed. The modified Becke-Johnson exchange potential is used to evaluate the opto-electronic and thermo-electric properties. By replacing anions (Cl to I), the band gap of the studied material in the visible region has been tailored, from 2.9 eV to 2.65 eV, for renewable energy devices. In addition, various optical properties such as dielectric constant, refraction, absorption, optical conductivity, and optical loss factor have been analyzed for optoelectronic applications. With the replacement of anions (Cl to I), the peaks of maximum intensities shifted to lower energy to values of 7.2 eV, 6.2 eV and 5 eV for CuCaCl3, CuCaBr3 and CuCaI3 respectively. Furthermore, the BoltzTrap code has been used to discuss thermal conductivity, power factor, Hall coefficient, specific capacitance and electron densities in detail for thermoelectric applications. The CuCaX3 family of perovskites has been found to have bandgaps falling in the visible region for light-emitting diodes (LEDs). These also exhibit high thermal efficiency, making them potential multifunctional candidates for optoelectronic and energy harvesting applications.