This work focuses mainly on development of modulated surface texturing of Al substrate for thin-film, silicon-based, flexible solar cells. We compared the current roll-to-roll process at industrial level with a newly developed lab-scale texturing that offers better performance both with KOH and NaOH etching of Al foil. The kinetics of these etching chemicals, modelled with an Arrhenius equation, is evaluated in both methods, activation energy and pre-exponential factor are calculated depending on etching concentration. We also deployed a new roll-to-roll experiment that shows better optical properties than the baseline. Finally, we also show the first results of micromorph tandem devices on the baseline texturing.

In this work we focus on texturing Al substrate in order to employ the modulated surface texturing approach for thin-film, flexible, micromorph solar cells. We deployed two different methods to induce micro-craters in Al foil, i) bare Al etching by KOH and ii) AZO sacrificial layer etched in KOH. After modelling the etching kinetics of KOH on Al, we characterized the 2D correlation length and rms roughness of these samples and find the optimal aspect ratio of 12% to deposit high-quality 3 µm-thick nc-Si. Finally, excellent angular scattering properties have been measured for both employed methods.