Studies on the Effect of Texture Additive in Silicon Solar Cells

Fabrication of high efficiency silicon solar cells with low cost is an important measure in silicon solar cell production. Silicon solar cell industries and technologists have started using alternate or advanced materials in conventional silicon solar cell process to enhance the electrical performance without compromising the quality and cost of the cell. Among the alternate materials, texture additives and metallization products play a significant role in solar cell production because it enhances the performances with lower cost or the cost at par in production. Industries deal with alkali texturization use either only IPA or IPA with texture additive as a wetting material for uniform texturization and thus reduce reflection and increase absorption of incident light. The influence of surface morphology on the solar cell parameters is essential for further improving cell efficiency. In this work, we report the optimization of texturization process by replacing IPA concentration by a texture additive without IPA. The process optimization with respect to time and concentration will be presented. Optical and morphological studies on wafers processed with IPA and IPA free texture additive has been carried out and interpreted with electrical performance. It is found that within the pyramid size studied here, there is no significant variation in reflectance and the short-circuit current. However, fill factor, open-circuit voltage and efficiency are significantly impacted by the pyramid size and height distribution. While cells with KOH/Texture additive texturization gives high fill factor (>79%), it is proved that an average fill factor gain of up to 1% absolute can be achieved by using the KOH/TA texturization process.