Fig. 7.
(a) Schematic of three electrode setup for EC and PEC measurements, (b, c) Timing diagram for applied potential (black line) and generated electrochemical current (blue line) for the 1st and the 6th cycles in the dark environment and under solar light illumination for (b) stoichiometric Cu2Se and (c) non-stoichiometric β-Cu1.3Se NCs (Black downward arrows present corresponding times when solar simulator is turned on. There is a two-minute interval (not shown here) between the end of 6th cycle in dark and start of 1st cycle under solar light illumination, and (d) comparative first cycles CV curves for both electrode materials.