Time‐Resolved Photocurrent of WSe₂ Photoanode Studied with a Nanosecond Pulse Laser

Fast photocurrent transients were measured at single crystalline electrodes employing a nanosecond ruby laser as a light source. Dependence of the transients on laser intensity showed that the photocurrent intensity increased proportionally to the laser intensity below ∼100 nJ/pulse. With more intense light, the photocurrent intensity showed a saturation, and the shape of the transient was deformed, being accompanied with a structure. The transient photocurrent due to the photocorrosion was suppressed by the addition of EDTA or Ag⁺. Influence of redox reagents, such as and , on the photocurrent transient was investigated. Dependence of decay time on bias voltage and load resistance showed that the decay time was determined by the RC time constant of the cell system. The flatband potential can easily be determined by this technique plotting vs. or by considering the onset of photocurrent, as disturbances are low due to the small absolute number of photogenerated carriers involved.