Impact of Angular Irradiation Profiles on Performance of Silicon PV Modules Using Light Scattering Films

Light trapping strategies, such as light scattering films (LSFs) present an opportunity to increase the power generated by Si photovoltaic modules. Evaluation of the benefits of these strategies for manufacturing decisions currently relies on current-voltage measurements performed using solar simulators under standard test conditions, with uncertainties representing expected variations due to different angles of incidence that result from the light sources of solar simulators. The practical achievement of normal incidence is challenging and consequently the angular irradiation profile varies between different solar simulators. In this article, we show that use of LSFs can enhance the short circuit current density, J
_SC
, of modules by 2.5% under normal incidence as compared to enhancements of 2.33%, 2.12%, and 1.56% measured using three different solar simulators (two short-tunnel and one table). This variation is due to the less effective light trapping of LSFs under more diffuse light. The angular response of these LSF modules on electricity yield is demonstrated through simulations using the angular matrix framework and SunCalculator software. The average J
_SC
enhancement varies from 1.46% (Cologne) to 1.63% (Alice Springs) corresponding to a decrease in diffuse irradiation at Alice Springs. Differences in measured J
_SC
from three solar simulators can result in the predicted average J
_SC
enhancements varying from -0.07% to 0.87% absolute, with the table simulator more closely predicting the average J
_SC
enhancement. This highlights the importance of considering the angular profiles of solar simulators if electricity yield and hence returns on investment for PV deployments is to be more accurately predicted.