  Lead-free double perovskites are overtaking single perovskites as solar
harvesting materials due to their superior stability, excellent catalytic
efficiency and minimal toxicity. In this investigation, we have synthesized
double perovskite Gd$_{2}$FeCrO$_{6}$ (GFCO) nanoparticles for the first time
via a facile sol-gel technique to investigate their structural, magnetic and
optical properties. The double perovskite GFCO crystallized in monoclinic
structure with P2$_1$/n space group. The Fe/Cr-O bond length was calculated as
$\sim$1.95 angstrom from the Raman spectrum which was consistent with the
value, $\sim$1.99 angstrom obtained from X-ray diffraction analysis. The
average size of the nanoparticles was determined to be $\sim$70 nm by both
field emission scanning electron microscopy and transmission electron
microscopy. The existence of mixed-valence states of Fe and Cr was confirmed by
X-ray photoelectron spectroscopy. The zero-field cooled (ZFC) and field cooled
(FC) curves largely diverged below 20 K. A downturn was observed in the ZFC
curve at 15 K which corresponds to an antiferromagnetic, N\'eel transition. The
narrow magnetic hysteresis loop recorded at 5 K was nearly saturated and
demonstrated an asymmetric shift along the magnetic field axis indicating the
concurrence of ferromagnetic and antiferromagnetic domains in GFCO
nanoparticles. The UV-visible and photoluminescence spectroscopic analyses
unveiled the semiconducting nature of nanostructured GFCO with an optical band
gap of 2.0 eV. The as-synthesized thermally stable lead-free GFCO semiconductor
might be a potential perovskite material to be employed in photocatalytic and
related solar energy applications due to its ability to absorb the visible
spectrum of the solar light efficiently
