Fabrication of External Contacts for Thin-film III-V Solar Cells using Inkjet Printing

We report on the development of external contacts for thin-film III-V solar cells. To this end, a novel approach that involves an isolation polymer layer deposited using inkjet printing before the deposition of metal contact layers is introduced. Details of the optimized printing process for depositing polymer bridges, which serve as a scaffold for the subsequent conductive metal layer deposition, are presented. The printing parameters are optimized to achieve high-resolution patterns (5080 DPI). Optimal print quality and resolution are attained at a drop spacing of 5 μm. The feasibility of the hybrid contact fabrication method is validated by demonstrating successful integration of external contacts on GaAs thin-film solar cells. This technique can be extended to fabrication of external contacts on multi-junction thin-film solar cells fabricated via epitaxial lift-off, alleviating degradation factors involved in standard contacting techniques.