Conclusion
The test setup allows to conduct various photoelectrochemical measurements (e.g., STH determination) and can help to avoid common problems with equipment. It allows the use of standard vertical solar simulators by reflecting the light to the electrochemical cell with a solar-grade mirror. The light in the plane of the photoelectrode had a high spectral quality, a low spatial non-uniformity and a low temporal instability, resulting in an AAA classification (IEC 60904-9). A system for temperature control with an external Peltier element allows measurements at constant temperature (±1 °C) in the range of 20–45 °C. It enables automated time resolved measurements with enhanced metrological precision and the investigation of the temperature dependency of photoelectrochemical reactions. Gas analysis is carried out with a mobile GC, which is equipped with a thermal conductivity sensor, two short columns and an internal gas supply. It makes use of an automated measurement routine with discontinuous sampling from the reactor cell. A software for data evaluation calculates Faraday and STH efficiencies and allows the correction of leakage. The system was applied to investigate a copper indium gallium selenide photocathode in H2SO4, for which a Faradaic efficiency of (95.4±7.7) % was determined.