Size and Concentration Determination of Colloidal Nanocrystals by Small-Angle X-ray Scattering
Résumé
The accurate determination of the dimensions of a nano-object is paramount to the development of nanoscience and technology. Here, we provide procedures for sizing quasi-spherical colloidal nanocrystals (NCs) by means of small-angle x-ray scattering (SAXS). Using PbS NCs as a model system, the protocols outline the extraction of the net NC SAXS pattern by background correction and address the calibration of scattered x-ray intensity to an absolute scale. Different data analysis methods are compared, and we show that they yield nearly identical estimates of the NC diameter in the case of a NC ensemble with a monodisperse and monomodal size distribution. Extending the analysis to PbSe, CdSe and CdS NCs, we provide SAXS calibrated sizing curves, which relate the NC diameter and the NC band-gap energy as determined using absorbance spectroscopy. In comparison with sizing curves calibrated by means of transmission electron microscopy (TEM), we 1
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