  Opto-spintronics is an emerging field where ultra-thin
magnetic-semiconductors having high spin-valley coupling play an important
role. Here, we demonstrate substitutional vanadium (V) doping in MoS$_2$
lattice in different extent, leading to the coexistence of photoluminescence
(PL), valleypolarization (~32%), and valley splitting (~28 meV shift in PL with
helicity $\sigma^+$ and $\sigma^-$ of light excitation). A large V doping
causes semiconductor to metal transition in MoS$_2$ but with medium level
causing the existence of photoluminescence with high spin polarization. The
ambipolar nature of medium level V doped MoS$_2$ is shown here indicating its
potential as an opto-electronic material. The presence of V-dopants and their
different level of content are proven by both spectroscopic and microscopic
methods.A detailed temperature and power dependent photoluminescence studies
along with density functional theory-based calculations in support unravels the
emergence of the co-existence of spin-valley coupling and photoluminescence.
This study shows the potential of doping MoS$_2$ for deriving new materials for
next generation room temperature opto-spintronics.
