Investigating Industrial Metallization Solutions for Double-side Contact Passivated biPoly Solar Cells

Double-side contact passivated silicon solar cells offer a high efficiency potential by reducing metal-semiconductor recombination at both the front and rear contacts. In this work, we explore three potential industrial metallization solutions for double-side contact passivated silicon solar cells, namely, (i) deposition of transparent conductive oxides (TCO), and subsequent low temperature (low-T) screen printing, (ii) conventional high temperature (high-T) fire-though screen printing, deploying a rear-side poly-Si(p
⁺
)/poly-Si(n
⁺
) tunnel junction and (iii) Front-side plating and rear-side high-T screen printing, deploying a rear-side poly-Si(p
⁺
)/poly-Si(n
⁺
) tunnel junction. On a precursor as well as on a device level, we demonstrate the feasibility and the potential of deploying carrier selective passivated contacts on both sides of a silicon solar cell. Using TCO and low-T screen printing as well as bifacial high-T screen printing, we demonstrate promising high V
_oc
values. The efficiencies of our very first biPoly cells are limited by low current, as expected, as we used only "moderately thick" (50 nm or 250 nm) poly-Si layers at the front side (instead of "ultra-thin" layers less than 10 nm) for first device integration.