  Recently, holey graphene (HG) has successfully synthesized at atomic
precision of hole size and shape. This shows interesting physical and chemical
properties for energy and environmental applications. Shaping of the pores also
transforms semimetallic graphene to semiconductor holey graphene, which opens
new door for its use in electronic applications. We systematically investigated
the structural, electronic, optical and thermoelectric properties of HG
structure using first-principles calculations. HG was found to have a direct
band gap with 0.65 eV (PBE functional), 0.95 eV (HSE06 functional) and HSE06
functional is in good agreement with experimental results. For the optical
properties, we use single-shot G0W0 calculations by solving the Bethe-Salpeter
equation to determining the intralayer excitonic effects. From the absorption
spectrum, we obtained the optical gap of 1.28 eV and a week excitonic binding
energy of 80 meV. We have found the large values of thermopower of 1662.59
$\mu$V/K and better electronic figure of merit, ZT$_{e}$ as 1.13 from the
investigated thermoelectric properties. Our investigations exhibit strong and
broad optical absorption in the visible light region, which makes HG monolayer
a promising candidate for optoelectronic and thermoelectric applications.
