As compared with either the temperature-elevated immersion
dyeing process or fast dyeing methods mentioned above, the
solution dropping method reported herein is an easier, greener
(less chemical waste), and more reliable TiO2 dyeing method.
A very short period of time (5 min) and minimum dye solution
(≤30 μL) are required in the solution dropping process of
dyeing TiO2 electrodes (with an active area of 0.4 cm × 0.4
cm). There is nearly no organic solvent waste or leftover dye
substance from such a solution dropping method. Neither
complicated equipment nor extra investment is needed