The effect of atmospheric cold plasma cleaning of FTO substrates on the quality of TiO2 electron transport layers for printed carbon-based perovskite solar cells

Abstract

In this work, TiO2 electron transport layers (ETL) of printed perovskite solar cells with back carbon electrode (C-PSCs) were prepared on uncleaned, chemically cleaned, and plasma-treated FTO substrates. The effect of cleaning procedure type on the quality of TiO2 ETL has been characterised by XPS and SEM. The C-PSCs with FTO substrates treated by low-temperature atmospheric plasma at ambient air for 10 s reached approximately the same efficiency (4.4%) as with the chemically cleaned FTO (4.5%). From optical microscope and SEM images, it was observed that the plasma cleaned the FTO substrate to some extent, thereby reducing the number of defects and pinholes occurring in the blocking layer. XPS measurements confirmed that chemical and plasma treatment significantly reduced organic species on the FTO surface.