Effects of localized tensile stress on GaAs solar cells revealed by absolute electroluminescence imaging and distributed circuit modeling

The effects of localized tensile stress (LTS) on Gallium Arsenide (GaAs) solar cells were investigated using an innovative methodology that integrated absolute electroluminescence (EL) imaging with three-dimensional (3D) distributed circuit modeling. Absolute EL imaging and spectra analysis revealed an enhancement in EL intensity and a red-shift in the EL emission peak within LTS-affected regions. The observations were well-interpreted by changes in the localized energy band structure. Utilizing the absolute EL image and spectra, the stress distribution on the surface of the GaAs solar cell after introducing LTS could be quantitatively determined. To quantify the observations from an electrical perspective, a 3D distributed circuit model of the GaAs solar cell was established. This model demonstrated that LTS led to a decrease in localized series resistance and an increase in localized shunt resistance. By introducing LTS, our model predicted a power conversion efficiency (PCE) increment in the solar cell under AM 1.5G 1-sun illumination, which was confirmed by the experimentally observed PCE increment. This research provided a comprehensive approach for analyzing and understanding the effects of mechanical localized stress on photovoltaic devices.