Observation of correlated barrier hopping in blue luminescent PbI2 nanoparticles

Hexagonally shaped lead iodide nanoparticles were synthesized by a simple chemical route. Well crystallized nature of the sample was confirmed by X-ray diffraction patterns. Transmission electron microscopy shows that the particles are hexagonally shaped and the average particle size is estimated to be 16-18 nm. The band gap of the nanoparticles was found to be 3.54 eV. Photoluminescence spectra show some distinct blue light emission in the visible region around 408 nm. Mechanism of dc and ac transport was analyzed in the temperature range 298-523 K and in the frequency range 20 Hz-2 MHz. The activation energies are estimated from both dc and ac data and found to be in good agreement. (C) 2014 Elsevier B.V. All rights reserved.