The ratio of the Gibbs energy gain per unit time per m 2 of surface exposed to the sun and the solar irradiance, E, integrated between λ = 0 and λ = ∞.
See also: photoelectrolytic cell
Source:
PAC, 1996, 68, 2223. 'Glossary of terms used in photochemistry (IUPAC Recommendations 1996)' on page 2274 (https://doi.org/10.1351/pac199668122223)