Development of a growth model for aluminum-doped zinc oxide nanocrystal synthesis via the benzylamine route

This work deals with time-resolved accessibility of suitable measurement technique to the solvothermal non-aqueous sol–gel synthesis of aluminum-doped zinc oxide (AZO) nanocrystals via the benzylamine route. Taking into account some limitations, we develop a new concept for using a lab-scale small-angle X-ray scattering (SAXS) camera to obtain detailed information about ongoing particle formation processes during AZO synthesis at the nanoscale range of 10 − 75 nm. Based on this concept, a new growth model is derived providing deep insights regarding process kinetics and morphological changes of AZO during growth. For this purpose, a new method is developed for carrying out and analyzing AZO synthesis in a low process temperature range (≪200 ° C) in order to achieve higher resolution of time-dependent particle formation processes by slowing down process speed. In detail, we show that the consumption of the zinc precursor during synthesis can be recorded by quantitative phase analysis (QPA) and thus validated with gravimetric analysis proving a pseudo-first-order process kinetics for the overall synthesis process. Taking into account the kinetics data, further transmission electron microscopy (TEM) and SAXS analyses are performed to investigate changes in terms of shape, size, and fractal properties leading into the development of a generalized growth model for AZO nanocrystals during synthesis.

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