Monitoring carrier transport and recombination in photovoltaic devices in real time
Abstract
Transport and recombination of excess carriers in an InGaAs solar cell are investigated by using time-resolved photoemission spectroscopy. We found that photovoltage rises and decays over 820 ps and 980 ps, respectively, at the pump fluence of 0.16 μJ/cm2. This result shows that charge separation and recombination occur in a close time scale while charge separation is substantially faster than recombination in a GaAs solar cell which we studied in the previous study. This implies that the InGaAs cell suffers from higher non-radiative recombination loss. We also analyze the limiting factor of the temporal resolution for the present technique. The temporal resolution can be improved by employing a light source with a higher photon energy while its benefit is not drastic. Alternative methods for the improvement are discussed. In addition, time-resolved photoluminescence spectroscopy was performed in order to compare the two time-resolved techniques. The photoluminescence decay of a GaAs cell shows a fast decay at a weak photo-injection level, which becomes slower at higher injection levels as observed in previous studies.
- Publication:
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Physics, Simulation, and Photonic Engineering of Photovoltaic Devices VIII
- Pub Date:
- February 2019
- DOI:
- 10.1117/12.2507736
- Bibcode:
- 2019SPIE10913E..0YH