  We employ a first-principles computational workflow to screen for optically
accessible, high-spin point defects in wide band gap two-dimensional (2D)
crystals. Starting from an initial set of 5388 point defects, comprising both
intrinsic and extrinsic, single and double defects in ten previously
synthesised 2D host materials, we identify 596 defects with a triplet ground
state. For these defects, we calculate the defect formation energy, the
hyperfine (HF) coupling, and the zero-field splitting (ZFS) tensors. For 39
triplet transitions exhibiting particularly low Huang-Rhys factors, we
calculate the full photo-luminescence (PL) spectrum. Our approach reveals many
new spin defects with narrow PL line shapes and emission frequencies covering a
broad spectral range. Most of the defects are hosted in hexagonal BN, which we
ascribe to its high stiffness, but some are also found in MgI2, MoS2, MgBr2 and
CaI2. As specific examples, we propose the defects vSMoS0 and NiSMoS0 in MoS2
as interesting candidates with potential applications to magnetic field sensors
and quantum information technology. All the data will be made available in the
open access database QPOD.
