Improved Layer Properties Combined with Light Soaking Enabling for 23% Efficient Silicon Heterojunction Solar Cells
Silicon hetero junction (SHJ) cell technology is one of the next generation high efficiency concepts that are currently in the focus of the PV community enabling record efficiencies and increasing in market share. Continuous process improvements along the production chain enable efficiency as well as yield improvements targeting cost reduction and increased market acceptance. This work addresses process improvements in our PV-TEC pilot production environment concerning amorphous silicon (a-Si) and transparent conductive oxide (TCO) layer deposition, and specifically presents a laser-based light soaking treatment enabling cell efficiency gains up to 0.6%abs. All implemented improvements enable for 23% efficiency on full area (244.43 cm2 ) SHJ cells. Investigations concerning the impact of the TCO edge exclusion on cell parameters by designated area IV-measurements with varying mask widths indicate that for 3 mm edge exclusion carrier collection and recombination losses which strongly affect JSC and FF can be reduced enabling for efficiencies of 23.5%.