Prepare two solutions of cobalt and sodium carbonate in water with a molar ratio of 1:2.1 separately. You need some excess sodium carbonate. Then you can take cobalt solution in a vial and put it under sonication. Add sodium carbonate while it is sonicating.
See the following papers:
Strategy for Tuning the Photophysical Properties of Photosensitizers for Use in Photodynamic Therapy
Chemistry–A European Journal 21 (41), 14440-14446
Anion-controlled morphologies and spectral features of cyanine-based nanoGUMBOS–an improved photosensitizer
AN Jordan, S Das, N Siraj, SL de Rooy, M Li, B El-Zahab, L Chandler, ...
Nanoscale 4 (16), 5031-5038
Tunable near-infrared emission of binary nano-and mesoscale GUMBOS
Prepare two solutions of cobalt and sodium carbonate in water with a molar ratio of 1:2.1 separately. You need some excess sodium carbonate. Then you can take cobalt solution in a vial and put it under sonication. Add sodium carbonate while it is sonicating.
See the following papers:
Strategy for Tuning the Photophysical Properties of Photosensitizers for Use in Photodynamic Therapy
Chemistry–A European Journal 21 (41), 14440-14446
Anion-controlled morphologies and spectral features of cyanine-based nanoGUMBOS–an improved photosensitizer
AN Jordan, S Das, N Siraj, SL de Rooy, M Li, B El-Zahab, L Chandler, ...
Nanoscale 4 (16), 5031-5038
Tunable near-infrared emission of binary nano-and mesoscale GUMBOS
Take Cobalt nitrate and sodium carbonate in appropriate staichiometric ration by using their density values and solubility in the water. Generally, you should take sodium carbonate more than precursor. The preferred ration is 1 cobalt nitrate : 2 sodium carbonate and continue this reaction under sonicator. Hope best for u