Two-dimensional <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>Re</mml:mi><mml:msub><mml:mi mathvariant="normal">S</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math> : Solution to the unresolved queries on its structure and inter-layer coupling leading to potential optical applications

Over the last few years, $\mathrm{Re}{\mathrm{S}}_{2}$ has generated a myriad of unattended queries regarding its structure, concomitant thickness-dependent electronic properties, and apparently contrasting experimental optical response. In this paper, with elaborate first-principles investigations, using density functional theory (DFT) time-dependent DFT, we identify structure $\mathrm{Re}{\mathrm{S}}_{2}$, which is capable reproducing analyzing layer-dependent The theoretical results are further validated by an in-depth structural, chemical, optical, optoelectronic analysis large-area thin films, grown chemical vapor deposition (CVD) process. Micro-Raman, x-ray photoelectron spectroscopy, cross-sectional transmission electron microscopy, energy-dispersive have enabled optimization uniform growth CVD films. correlation between properties was established static photoluminescence excited state transient absorption measurements. Sulfur vacancy-induced localized mid-gap states render significantly long lifetime excitons in these ionic gel top-gated photodetectors, fabricated from as-prepared exhibit large photo-response $\ensuremath{\sim}5$ A/W remarkable detectivity $\ensuremath{\sim}{10}^{11}$ Jones. outcome paper will be useful promoting application vertically films field optics opto-electronics.