Screen‐Printed Electrically Isolated Buried Contacts for Metal‐Halide Perovskite/Silicon Tandem Solar Cells: Proof of Concept Devices and Electrical Loss Simulations Highlighting Large‐Scale Potential

abstract

Processes for applying front metallization to metal‐halide‐perovskite (MHP)/Si tandem solar cells must carefully account for the intrinsic stability challenges of MHPs—particularly their susceptibility to thermal degradation. The paper presents a proof‐of‐concept for a novel interconnection design for MHP/Si tandem solar cells, named electrically isolated buried contacts (EIBC). This innovative approach involves screen‐printing contacts onto a screen‐printed isolating solder resist layer on the Si bottom solar cell before the MHP top solar cell is fabricated. This method allows the contacts to undergo high‐temperature annealing, enhancing their conductivity. Through the use of SpiceGUI simulations together with the evaluation of several resistive contributions in test samples, it is demonstrated that EIBC contacts sintered to 350 °C can improve cell efficiencies on M10 solar cell sizes compared to low temperature screen‐printing methods (sintered at 150 °C) by 3.8%abs. for 2.2 mm finger pitch and 2.6%abs. for 1.4 mm finger pitch. Screen‐printed EIBC contacts are also promising for cost‐effective and long‐term stable industrial integration of tandem solar cells into modules via soldering as the mechanical stress on top of the MHP layer can be reduced.