Transparent conducting oxides (TCOs) are materials with low optical absorption in the visible, which makes them particularly suitable for key applications in information technologies (OLED´s, displays…) and energy harvesting (photovoltaics). Recently [1],  the feasibility of producing highly anisotropic resistivity surfaces by fs-laser irradiation of ITO films at high repetition rate at 1030 nm has been demonstrated. Electrical and optical anisotropies appear as a consequence of the formation of Laser Induced Periodic Structures (LIPSS) at the material surface. These structures can be useful for applications ranging from conductive flexible paths (ACFs), and electrolytes in Li-ion batteries, to interfacial buffer layers for bulk heterojunction organic solar cells.

Still, the problem of In resources is making other TCO´s to acquire a much relevant role. Among them, the excellent properties of Fluorine-doped Tin Oxide (FTO) are making this material a favourite choice for many applications. In this work we have analysed the production of optical and electrical anisotropic FTO surfaces through the coherent formation and propagation of LIPSS upon irradiation of thin FTO films by fs-laser processing. The parameters leading to the best performing structures as well as the role of the compositional changes, in particular the F/Sn compositional ratio, in the morphology and material properties evolution will be analysed.

[1] C. Lopez‐Santos, D. Puerto, J. Siegel, M. Macias‐Montero, C. Florian, J. Gil‐Rostra, V. López‐Flores, A. Borras, A. R. González‐Elipe, J. Solis, Adv. Opt. Mater. 2020, 9, 2001086