Copper-Based Volumetric Filler Dedicated for Ag Paste for Depositing the Front Electrodes by Printing on Solar Si Cells

Abstract

In this work we present research results on a new paste NPCuXX (where: NP—new paste, CuXX—component, XX—a modifier consisting of Ni and other important elements) based on a copper composite (CuXX) for fabrication of front electrodes in silicon solar cells. The CuXX composite is obtained by chemical processing of copper powder particles and can be used in two ways: as an additive to commercially available paste or as a base material for a new paste, NPCuXX. The CuXX offers the possibility to exchange up to 30 and 50 wt.% Ag into Cu, which significantly decreases the solar cells material costs, and therefore, the overall solar cell price. Emphasis was placed on a proper mass suitable fabrication process of the CuXX component. The NPCuXX paste has been applied both to conventional cell structures such as aluminum-back surface field (Al-BSF) and passivated emitter and rear contact (PERC), and finally solar cells with front electrodes deposited by screen-printing method were fabricated and characterized by current-voltage techniques. This paper reports the first implementation of the copper volumetric material into a screen print paste used in a high-temperature metallization process to fabricate the front contacts of Si solar cells with a highest fill factor of 77.92 and 77.69% for the abovementioned structures, respectively.

Silicon solar cells and modules with front contact paste containing copper‐based component

“…It was found that the obtained solar cells showed parameters comparable with the ones with pure Ag commercial metallization. Moreover, the results also indicate that the XX protective coating properly blocks the diffusion of Cu atoms to the p – n junction 19 …”

Model of boron diffusion in silicon used for solar cell fabrication based on boric acid solutions

“…The model’s big advantage is taking into account the influence of the boric acid concentration in dopant sources on final concentration profiles of the obtained layer. This enables determination of concentration profiles for intermediate parameters of the diffusion doping process, and the obtained results may be used instead of time-consuming and costly SIMS measurements, which facilitates focusing on optimizing other technological processes of solar cell fabrication, such as production of electrodes (Musztyfaga-Staszuk et al , 2018; Drabczyk and Panek, 2014; Musztyfaga-Staszuk and Dobrzanski, 2014), an anti-reflective layer (Swatowska, 2018; Swatowska et al , 2011) or a surface texture on the top of wafer (Kulesza-Matlak et al , 2018; Kulesza et al , 2014).…”