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We present metal wrap through (MWT) silicon solar cells with passivated surfaces based on a simplified device structure. This so-called HIP-MWT structure (high-performance metal wrap through) does not exhibit an emitter on the rear side and therefore simplifies processing. The confirmed peak efficiency of the fabricated solar cells with an edge length of 125 mm, screen printed contacts and solder pads is 20.2%. To our knowledge, this is the highest value reported for large-area p-type silicon solar cells to date. Schematic structure of the fabricated HIP-MWT solar cell

RCA cleaning in multiple variations is widely used in photovoltaic production lines for high efficiency solar cells. These commonly peroxide based cleaning procedures are effective, but suffering from large chemical consumption and waste generation. A substitution of hydrogen peroxide by ozone in cleaning solutions is not realized yet for PV devices despite its high oxidation potential and facility advantages. The very high potential of ozone cleaning has been shown in various microelectronic applications [1-7]. Dissolved ozone in HF/HCl solution gives the option of cleaning by combined silicon etching and oxidizing as well as complexing metal contaminations due to F- and Cl-.

Potassium Hydroxide (KOH) and Isopropanol (IPA) are currently being used to texturize and reduce the reflectivity of mono crystalline (mono-c) silicon wafer surfaces during the manufacturing of solar cells. One concern with this process is that the IPA is volatile which can lead to high replenishment rates, poor process stability, and increased costs. The flammable nature of the IPA should also be highlighted which can lead to handling and safety concerns. The goal of this work was to develop an IPA free process that does not compromise texturing or cell performance while providing improved process control. A secondary goal was to develop a chemistry that would allow for in-line texturing of mono-crystalline substrates

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