Figure 2.

(a) Concentration of Cu_xO colloids synthesized at 0 V for various repetition rates from 1 kHz up to 15 kHz. The optimal repetition rate was determined at ∼5.1 kHz. (b) Concentration of Cu_xO colloids synthesized at 5.1 kHz for various potential differences from 0 V up to 1000 V. Inset: Photo of the colloids synthesized at 5.1 kHz under various potential differences. (c) pH of the Cu_xO colloids synthesized at 5.1 kHz versus the potential difference used during the synthesis. All of the pH values have been measured at room temperature (T ∼ 23 °C). (d) Temperature of the colloids synthesized at 5.1 kHz versus the potential difference used during the synthesis.