Modeling of photonic efficiency under controlled periodic illumination and continuous illumination

Abstract

Controlled periodic illumination has been used to increase photonic efficiency. However, the mechanism for the controlled periodic illumination is still under debate. Based on the excitation of the electron–hole pair, a mathematical model is developed to describe the photonic efficiency under controlled periodic illumination and continuous illumination. The photonic efficiency is inversely proportional to the average light intensity or duty cycle. The high photonic efficiency at low light intensity is because the photocatalyst is closer to the thermal equilibrium state than at high light intensity, meaning a weak irreversibility. The present model shows that the controlled periodic illumination under a high maximum light intensity is virtually the same as continuous illumination under a low light intensity. Good agreement is found between the experimental data and predictions. The present model correctly predicts the dependence of the photonic efficiency on the maximum light intensity with a very small relative error.