  Potential applications of monolayer of transition metal dichalcogenides
(TMDs) in optoelectronic and flexible devices are under heavy investigation.
Although TMDs monolayers are highly robust to external mechanical fields, their
electronic structure is sensitive to compressive and tensile strain. Besides,
intrinsic point defects are present in synthesized samples of these two
dimensional (2D) materials which leads to the modification of their electronic
and optical properties. Presence of vacancy complexes leads to absorption with
larger dipole matrix elements in comparison to the case of simple transition
metal vacancies. Using first principles calculations, we scrutinize the effect
of various strain situations on the absorption spectra of such defective
monolayers and show that strain engineering allows for reversible tuning of the
optical properties.
