Testing the Infrared Light Effect on c-Si PV Cells

In Photovoltaic panels, valence band electrons gain energy by absorbing a photon. The energy of the photon should be higher than the band gap. According to Einstein's quantum principle, low energy photons - having an energy lower than the bad gap energy - are not absorbed by valence electrons. This paper investigates the effect of low energy photons or infrared light on c-Si cells. For that, an apparatus has been developed with appropriate optical filters. The filters can transmit Infrared light, visible light, or a mix of visible and infrared light. Different tests like short-circuit current test, Maximum Power Point test, light soaking test, and direct test have been conducted to understand the effect of these low energy photons. Results showed that low energy photons do not contribute to photogeneration. Although they contribute to useful work at the output of the panel they don't have high efficiency. Otherwise, low energy photons, mainly infrared light is responsible of the heating effect of PV cells.