Morphology-Tailored Synthesis of PbSe Nanocrystals and Thin Films from Bis[N,N-diisobutyl-N′-(4-nitrobenzoyl)selenoureato]lead(II)

The ligand N,N-diisobutyl-N'-(4-nitrobenzoyl)selenourea (4-NO2-C6H4CONHCSeNiBu2) (1) and its complex {bis[N,N-diisobutyl-N'-(4-nitrobenzoyl)selenoureato]lead(II)} [(4-NO2-C6H4CONHCSeNiBu2) Pb-II] (2) have been synthesized, and their structures determined by single-crystal X-ray methods. Compound 2 was employed as a single-source precursor (SSP) for the deposition of PbSe thin films by aerosol-assisted chemical vapor deposition (AACVD) in the temperature range 250-500 degrees C on glass substrates. The films obtained at low temperature consist of globular-shaped crystallites, whereas at higher temperature (ca. 500 degrees C) wirelike morphologies are dominant. PbSe nanocrystals were also prepared from compound 2 by solution thermolysis at 200-250 degrees C. Photoluminescence (PL) life time measurements based on the time-correlated single-photon-counting (TCSPC) technique showed significantly faster PL decay in as-prepared PbSe nanocrystals relative to previous reports. The purity and elemental composition of the as-deposited PbSe thin films and nanocrystals were determined by energy-dispersive X-ray analysis (EDX).