Structural and optical characterizations of multi-layered and multi-stacked PbSe quantum dots

Abstract

A multi-layered nanocomposite thin film was fabricated to increase the density of PbSe quantum dots. It consisted of low-loss polymer layers and multi-stacked PbSe quantum dot layers in series. The solutions of a UV-curable low-loss polymer and PbSe quantum dots were spin-coated layer-by-layer. An arrayed and multi-stacked PbSe quantum dot layer was self-assembled by spin-coating and solvent evaporation. The multi-stacked layers of PbSe quantum dots have a face-centred cubic structure with an average {111} plane distance of ∼6.1 nm, determined by small-angle x-ray scattering. The average diameter of PbSe quantum dots is ∼5 nm and the average interparticle spacing distance is ∼2.5 nm, characterized by transmission electron microscopy. The density of PbSe quantum dots in the single-arrayed layer is ∼1.8 × 1012 cm−2 and the density in the three-layered thin film of multi-stacked PbSe QDs is >1.6 × 1013 cm−2. The peak intensities of absorption and photoluminescence were increased with increasing number of PbSe quantum dot layers. The time of luminescence decay to e−1 is 138 ns at room temperature. We investigated the structures of multi-layered and multi-stacked PbSe quantum dot thin films as well as their optical properties, and then suggested their photonic applications.

Quasi‐Seeded Growth of Ligand‐Tailored PbSe Nanocrystals through Cation‐Exchange‐Mediated Nucleation

“…In general, the long lifetimes in Pb chalcogenide NCs are attributed to the effect of internal dielectric screening on the radiative recombination rate 11d. 21 In films, the oleate‐capped NCs exhibit much shorter radiative lifetimes ( τ 1/e =29 ns, see the http://www.wiley-vch.de/contents/jc_2002/2008/z705604_s.pdf) similar to those previously reported for PbS11c and PbSe NCs 22. This observation can be attributed to an increase of nonradiative recombination as a result of interparticle charge‐ and energy‐transfer processes23 and/or through the surface traps formed upon film preparation 24.…”

Synergism between lipoxygenase‐active soybean flour and ascorbic acid on rheological and sensory properties of wheat bread

“…In general, the long lifetimes in Pb chalcogenide NCs are attributed to the effect of internal dielectric screening on the radiative recombination rate 11d. 21 In films, the oleate‐capped NCs exhibit much shorter radiative lifetimes ( τ 1/e =29 ns, see the http://www.wiley-vch.de/contents/jc_2001/2008/z705604_s.pdf) similar to those previously reported for PbS11c and PbSe NCs 22. This observation can be attributed to an increase of nonradiative recombination as a result of interparticle charge‐ and energy‐transfer processes23 and/or through the surface traps formed upon film preparation 24.…”

Site-Selective Optical Coupling of PbSe Nanocrystals to Si-Based Photonic Crystal Microcavities

“…Our PbSe nanocrystals exhibit photoluminescence quantum efficiency up to 40% in solution for emission at 1.55 μm, while the efficiency reduces to a few percent in drop-cast solid form . We found that monolayer coverages of PbSe nanocrystals grafted on H-terminated Si are emissive for several months when kept in vacuum.…”