• We study raw and annealed kesterite nanocrystals through a synergistic multi-technique approach. • In the annealed samples a minor presence of a secondary phase could be detected. • Annealing promotes the formation of paramagnetic vacancies. • Iron doping results in the incorporation of both Fe +2 and Fe +3 ions in the system. • Thermal treatment favors the occurrence of magnetically-active complex defects.
Millacci et al. (Fri,) studied this question.