Theoretical Calculations Meet Experiment to Explain the Luminescence Properties and the Presence of Defects in m‑ZrO2

The present article is a thorough quantum mechanics investigation based on the DFT method targeting the opto-electronic properties of the m-ZrO2 material issuing from the presence of defects. Herein, we conclude that the luminescence observed around 477 nm (∼2.60 eV) corresponds to the charge transfer between TiZr and oxygen atoms (i.e., Ti3+ + O– → Ti4+ + O2–), and not from oxygen vacancies or d-d transitions at Ti3+ sites. Namely, on the basis of constrained DFT calculations, an emission at 2.61 eV (475 nm) was calculated that matches perfectly with experiments (around 2.60 eV/477 nm). Moreover, in order to demonstrate the propensity of the ZrO2 host lattice to entrap titanium, intrinsic and extrinsic point defect formation energies on m-ZrO2 were computed.