In a recent paper in Energy. Environ. Sci. Döscher, et al. examine various contributions to error in reporting solar-to-hydrogen efficiency (Energy Environ. Sci., 2016,9, 74-80). They examine an array of factors including the spectral distribution of flux and how differences in intensity at specific wavelengths influence the overall performance of water-splitting photoelectrodes.

Their findings suggest a key set of experimental precautions to avoid when performing photoelectrochemical experiments in order to limit experimental error: disclosure of the light source configuration, precise definition of device area and illumination area, measuring the quantum efficiency and correlating it with the solar-generation potential, and accurate measurement of Faradaic efficiency to understand potential side reactions.

Link to paper: Solar-to-hydrogen efficiency: shining light on photoelectrochemical device performance