Experimental and theoretical studies of donor-acceptor scintillation from PbI2

► Undoped PbI2 is a moderately bright, fast scintillator at cryogenic temperatures. ► Luminosity drops above 40 K with a 4 meV barrier to the non-radiative channel. ► The emission peaks at 520 nm, 0.18 eV from the band edge. ► The radiative center can be a lead/iodine vacancy donor-acceptor pair. ► The acceptors Cu, Ag, and Te result in red-shifted slow scintillation.