THE INVESTIGATION OF DONOR AND ACCEPTOR STATES IN NANOPARTICLES OF THE LAYERED SEMICONDUCTOR PBI2

The low-temperature luminescence of PbI2 nanoparticles consists of exc iton lines in the region of similar to 2.49 eV and additional donor-ac ceptor recombination luminescent bands at lower energies, centered at 2.44 (green) and 2.07 eV (red). The correlation between donor-acceptor recombination emission processes and lattice imperfections was examin ed, utilizing optically detected magnetic resonance spectroscopy. The results identified the following imperfection sites in both the green and red bands: an acceptor site, associated with an isotropic lead vac ancy defect, [V-](Pb)(2+) and a donor site, associated with an anisotr opic iodine vacancy, [V-0](iodine). Thus, the results suggest that the red band corresponds to stoichiometric defects at the surface, while the green band corresponds to the same stoichiometric defects at the i nterior part of the nanoparticles. (C) 1997 Elsevier Science B.V.