Roman Keding

TL;DR: In this paper, the first generation back-contact back-junction (BC-BJ) silicon solar cells with cell efficiencies well above 20% were fabricated, and the silicon-doping is performed from pre-patterned solid diffusion sources, which allow for the precise adjustment of phosphorus and boron doping levels.

TL;DR: The optimum ionomer content was found to be dependent on the operating point and condition, as well as catalyst loading and type, and the data set provided gives a starting point to further understanding of structured catalyst layers.

Abstract: Two approaches for structuring thin metal layers for seed and growth metallization for back-contacted solar cells using hot-melt inkjet as masking technology are evaluated. The characteristics of a hot-melt printed image relevant for process development are discussed. A metal lift-off process and a metal etching process, both creating a meander-shaped opening in a metal layer - hence an interdigitated grid - based on hot-melt inkjet are established. The process sequences are characterized regarding the shunt resistance between the grids and the contact resistance to an underlying emitter layer on appropriate test structures. The contact resistance is found to be increased on samples fabricated by metal lift-off compared to samples fabricated by metal etching. The lift-off process is found to open lines with a width of around 120 µm reliably, whereas a line opening width in the range of 50 µm is reliably represented with the etching process sequence, whereas a high shunt resistance is considered the criterion for a successful process.

TL;DR: In this paper, zincate solutions are investigated regarding their adhesion on typical solar cell surface morphologies, and sufficient adhesion is demonstrated by zincate processes with subsequent plating of nickel, copper and silver on both random pyramid and damage etched surfaces.

TL;DR: In this paper, different metallization approaches were investigated and compared with respect to their applicability for silicon heterojunction (SHJ) solar cells, and it was found that spreading of the ink is substantially reduced by choosing the optimum substrate temperature, enabling for a line width of 32 µm.