Suppressing Nanocrystal Growth with Cysteine: A Quenching Strategy for Monitoring the Evolution of Nanocrystals

Despite extensive studies on controlling the morphological and compositional structures of nanocrystals to adjust their physical and chemical properties, it is still challenging to verify the exact formation mechanism of nanocrystals. Here, we report an efficient cysteine-based quenching strategy that allows an unequivocal exploration of the growth process of nanocrystals. Intermediate nanostructures formed during the synthesis of various metal nanocrystals having different compositions and morphologies could readily be analyzed after the synthesis was quenched by adding cysteine to the reaction solution, enabling the revealing of nanocrystal growth mechanisms. This method exhibited distinctly high quenching ability compared to conventional quenching methods, which could be ascribed to the capability of cysteine for forming stable complexes with metal precursors and preventing intermediates from deformation and further growth. The present strategy will improve the understanding of the nanocrystal growth mechanism and, hence, provide an opportunity to devise unprecedented nanocrystal systems.