Time-Resolved Photoluminescence Spectroscopy Of Excitons In Layered Semiconductor Pbi2 Nanoclusters

We studied the dynamics of excitons excited in layered semiconductor PbI2 nanoclusters (NCLs) using time-resolved photoluminescence (TRPL) spectroscopy. TRPL spectra reveal formation of self-trapped excitons (STEs). It was shown that the formation of the STEs for larger [more than the Bohr radius of exciton in bulk PbI2 (R-B = 1.9 nm)] NCLs occurs in sub-nanosecond time scale, while in the case of small NCLs with sizes about R-B, it takes place in nanosecond scale. The effective energy transfer from the small to the larger semiconductor NCLs, which arises from dipole-dipole intercluster interactions, takes place in sub-nanosecond scale. We demonstrate that the STEs are stable states and they define effective radioluminescence of the investigated Pb1-XCdXI2 alloys. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4764315]