Considerations on the model-free shape retrieval of inorganic nanocrystals from small-angle scattering data

Some new considerations on the model-free shape retrieval of inorganic nanocrystals based on the evaluation of averaged dummy atom models obtained from small-angle X-ray scattering data are presented. Scattering curves for shapes commonly found in inorganic nanocrystal systems were computed, from which dummy atom models were reconstructed using DAMMIN and DAMAVER. Cross sectional analysis methods were applied to allow a quantitative interpretation of these models, where special focus was directed towards the measurement of discrete model dimensions. By a quantitative comparison of the obtained models with the initial geometries, the limits of the proposed evaluation techniques were tested. Further, the proposed methods were utilized to study the influence of the accessible scattering vector as well as the effect of increasing size distributions on models retrieved by DAMMIN and DAMAVER. The results confirm the usefulness of these ab initio shape-retrieval methods for slightly polydisperse systems. Finally, the practicability of the proposed techniques is demonstrated on an ensemble of chemically synthesized colloidal bismuth nanocrystals.