Luminescence of ternary nanoaggregates in CsI-PbI2 thin films

Thin films of about 400 nm thickness were grown by vacuum co-evaporation of powders of CsI and PbI2 compounds from two independent molybdenum crucibles on quartz and glass substrates. The absorption, luminescence and decay kinetics characteristics of thin films were measured in the temperature range 4-300 K. At 4.3 K the CsPbI3 aggregates show an emission peak around 535 nm and a smooth excitation spectrum with sharp excitonic peak around 406 nm. The Cs4PbI6 aggregates emission is centered around 430 nm with two characteristic excitation peaks around 365 and 290 nm. The Cs-4 PbI6 phase shows well-expressed two-component decay kinetics similar to that of Cs-4 PbX6 (X = Cl,Br) and KI: Pb bulk materials. X-ray diffraction spectroscopy confirmed the formation of CsPbI3 and Cs-4 PbCI6 nanoaggregates in the thin him samples. (C) 2000 Elsevier Science B.V. All rights reserved.