Modification of optical properties of fluorine-doped tin oxide (FTO) thin films by picosecond direct laser interference patterning

HERMAN HEFFNER; MARCOS SOLDERA; ANDRÉS FABIÁN LASAGNI

Darmstadt

Congreso; Materials Science and Engineering Congress (MSE); 2022

Deutsche Gesellschaft für Materialkunde (DGM)

Transparent conducting oxides (TCOs) have garnered much of the attention of the scientific community in recent decades due to their ability to function both as an optical window allowing light to enter, as well as a top electrode for high efficiency optoelectronic devices, such as thin film (CIGS/CdTe) and dye-sensitized solar cells (DSSCs). To meet this high-performance quota, work has been done to improve the its optical and electrical properties. Particularly, fluorine-doped tin oxide (F-SnO2; FTO) is the electrode of excellence in DSSC cells due to its low cost, thermal resistance and electronic compatibility. A well-known strategy to improve its optical properties is surface structuring to achieve an increase in direct (Tdir) and diffuse (Tdiff) transmittances.In this work, FTO thin films between 500 and 600 nm deposited on glass were structured by Direct Laser Interference Patterning (DLIP). The surface characterization exhibits periodic microchannels and micropillars, which act as diffraction grating yielding an increase in the average diffuse transmittance in the spectral range 400-800 nm. A partial deterioration on their conductivity is observed as a result of the removal of conductive material. This work proposes the feasibility of trading off a portion of the electrical conductivity in order to obtain a substantial improvement in the optical performance.