Recycling and reusing ITO substrates from perovskite solar cells: A sustainable perspective

Abstract

In the present work we have carried out two benign routes to recycle ITO coated glass substrates of perovskite solar cells (PSCs) using diluted potassium hydroxide (KOH) or citric acid solutions. After removal of the different layers of the cells structural, optical and electrical properties of ITO recycled substrates were characterized and compared with virgin ones. Sheet resistance and roughness measurements indicate that diluted KOH treatment is the preferred method as it leads to no detectable damage to the ITO coating. We also evaluate the factor of merit of ITO substrate taking into account transmittance and conductivity results obtaining similar values for KOH ITO recovered and original substrates. A new PSC device (with a wide bandgap perovskite absorber) using this recycled ITO was manufactured with identical power conversion efficiencies to the ones achieved with pristine substrates, in this case approx. 18 %.