Geometrical Morphology of Inkjet-Printed Finger Electrodes on Untreated Multi-Crystalline Silicon Solar Cells

The geometrical morphologies fabricated by continuous and interlacing printing modes on untreated multi-crystalline solar cells are quantitively explored for uniform and high aspect-ratio finger electrodes. The voltage waveform of printhead is well modulated by in-house developed inkjet prototype printer for optimizing the droplet volume and velocity. As the fingers are fabricated with continuous printing mode by varying printing parameters, the bulging and coffee ring morphologies could not be eliminated resulting from the rough and anisotropic features. The interlacing printing mode is first introduced for finger electrodes fabrication. Results show that the width of the printed finger is not influenced by the printing layers and maintains the stable values of ~60 μm with pre-heating temperature 80 °C. Moreover, the interlacing printing mode has a high tolerance of droplet spacing variance (30-45 μm) and suppresses the coffee ring morphology which obtains uniform finger electrodes. The study not only offers good guidance of finger electrodes fabrication for multi-crystalline solar cell manufacturing, but also proposes in-depth insights for the three-dimensional circuit structures fabrication of the emerging printed electronics.