In this paper, CdSe nanocrystal dissolution in an aqueous solution was studied. It was found that light is a key factor affecting the dissolution of nanocrystals. In the presence of light, the electrons generated from CdSe nanocrystals reduce water to hydrogen and hydroxide ions (OH − ) while photo-generated holes oxidize CdSe to Cd2 + and elemental Se. The dissolution was accelerated in an acidic medium while moderate alkalinity (pH = 10.3) can slow down the dissolution possibly due to precipitation of nanocrystals. This study has strong implications for the use of these crystals in aqueous environments (bioimaging and dye-sensitized solar cells).
Xi, L., Lek, J. Y., Liang, Y. N., Boothroyd, C., Zhou, W., Yan, Q., Hu, X., Chiang, F. B. Y., & Lam, Y. M. (2011). Stability studies of CdSe nanocrystals in an aqueous environment. Nanotechnology, 22(27), 275706. https://doi.org/10.1088/0957-4484/22/27/275706