Composition and size-dependent extinction coefficient of colloidal PbSe quantum dots

Moreels, Iwan; Lambert, Karel; de Muynck, David; Vanhaecke, Frank; Poelman, Dirk; Martins, José; Allan, Guy; Hens, Zeger

Type de document :

Compte-rendu et recension critique d'ouvrage

DOI :

10.1021/cm071410q

Titre :

Composition and size-dependent extinction coefficient of colloidal PbSe quantum dots

Auteur(s) :

Moreels, Iwan [Auteur]
Lambert, Karel [Auteur]
de Muynck, David [Auteur]
Vanhaecke, Frank [Auteur]
Poelman, Dirk [Auteur]
Martins, José [Auteur]
Allan, Guy [Auteur]
Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 [IEMN]
Hens, Zeger [Auteur]

Titre de la revue :

Chemistry of Materials

Pagination :

6101-6106

Éditeur :

American Chemical Society

Date de publication :

2007

ISSN :

0897-4756

Discipline(s) HAL :

Sciences de l'ingénieur [physics]

Résumé en anglais : [en]

Inductively coupled plasma mass spectrometry (ICP-MS) was combined with UV–vis−NIR spectrophotometry and transmission electron microscopy to determine the nanocrystal composition and molar extinction coefficient ϵ of ...
Lire la suite >Inductively coupled plasma mass spectrometry (ICP-MS) was combined with UV–vis−NIR spectrophotometry and transmission electron microscopy to determine the nanocrystal composition and molar extinction coefficient ϵ of colloidal PbSe quantum dot (Q-PbSe) suspensions. The ICP-MS results show a nonstoichiometric Pb/Se ratio, with a systematic excess of lead for all samples studied. The observed ratio is consistent with a faceted spherical Q-PbSe model, composed of a quasi stoichiometric Q-PbSe core terminated by a Pb surface shell. At high photon energies, we find that ϵ scales with the nanocrystal volume, irrespective of the Q-PbSe size. From ϵ, we calculated a size-independent absorption coefficient. Its value is in good agreement with the theoretical value for bulk PbSe. At the band gap, ϵ is size-dependent. The resulting absorption coefficient increases quadratically with decreasing Q-PbSe size. Calculations of the oscillator strength of the first optical transition are in good agreement with theoretical tight binding calculations, showing that the oscillator strength increases linearly with Q-PbSe size.Lire moins >

Langue :

Anglais

Vulgarisation :

Non

Collections :