Ab Initio DFT Perspective on Triclinic Bi₂CrO₆: Energy Material for Optoelectronic, Thermoelectric, and Photocatalytic Applications

Here we report comprehensive theoretical modeling of hydrothermally stabilized P1̅ bismuth chromate (Bi2CrO6). The desired crystallographic-elastic properties correlation, dynamical stability, and infrared and Raman absorptions of triclinic Bi2CrO6 were corroborated from the equation of state, elastic tensor, phonon density of states and band structures, and Raman tensor simulations, respectively. The sophisticated tuned hybrid functional in the presence of spin–orbit coupling reliably reproduced the diffuse reflectance spectroscopy-derived ∼2.19 eV direct electronic band gap of triclinic Bi2CrO6 along with its broad absorption range of ∼620 nm. Its average electron and hole effective masses turned out to be ∼4.27 and ∼2.40 times larger than the bare electron mass, respectively. The predicted dimensionless thermoelectric figure of merit ZT ≈ 0.37 at 600 K for triclinic Bi2CrO6 is on par with that of well-known n-type thermoelectric materials like SrTO3 and BaBi2O6. The steady-state photoluminescence emission of triclinic Bi2CrO6 occurred at 460, 468, 490, and 572 nm in the visible spectrum. The theoretical electronic band edge positions and reaction potential analysis supported the experimentally observed photocatalytic degradation of methylene blue and rhodamine B dyes. In summary, the results presented here may have validated the potential of triclinic Bi2CrO6 in optoelectronic, thermoelectric, and photocatalytic applications.