Development of eco-friendly cleaning solution for industrial silicon wafer solar cell

In the cleaning process to fabricate silicon solar cell wafers, removal of stains and metal impurities on the wafer surface is important since they can affect the surface texturing of silicon solar cells. The surfactants included in a cleaning solution used for the cleaning process have a significant effect on the detergency by slightly altering the temperature, concentration, or molecular structure of the adsorbent. In this study, the eco-friendly and reusable cleaning solution have been developed to remove the generation of stains and increase the recyclability of the cleaning solution by adjusting the ratio of polyoxyethylene lauryl ether, which is a nonionic surfactant with several advantages such as, no ion pollution and strong osmosis. The stain inspection revealed that the generation rate of stains reduced from 0.35% to 0.01% when the ratio of the polyoxyethylene lauryl ether included in the cleaning solution was the highest. It was confirmed that the cleaning solution with the highest ratio of polyoxyethylene lauryl ether can be reused over 60 times by the investigation of the concentration of metal impurities, the texturing result and the reflectance values. The cleaning solution with the highest ratio of the polyoxyethylene lauryl ether is the most suitable for the mass-production process, owing to the low generation rate of stains and re-useable solution.