Researchers from Chungnam National University and Russian Academy of Sciences have reported a method to increase the efficiency of perovskite solar cells (PSCs) by modifying the surface of a fluorine-doped indium tin oxide (FTO) substrate using an atmospheric pressure plasma treatment.
The surface modification of the FTO film involved several challenges, such as control of the blocking layer uniformity, removal of pinholes, and deposition of a dense layer. This strategy allows the suppression of charge recombination at the interface between the FTO substrate and hole conductor.
Electrochemical impedance spectroscopy analysis showed that the plasma treatment increased the charge transfer resistance between the FTO and hole conductor from 95.1 to 351.1 Ω, indicating enhanced resistance to the electron back reaction.
Analyses of the open-circuit photovoltage decay revealed that modification of the surface of the FTO substrate by plasma treatment increased time constant from 6.44 ms to 13.15 ms. The effect is ascribed to suppression of the electron recombination rate.
PSCs based on the plasma-modified FTO layers reportedly demonstrated a power conversion efficiency of 2.09%, which is 105% higher than that of PSCs with conventional untreated FTO layers and without a mesoporous TiO2 layer. Accordingly, the observed efficiency in PSC samples using a mesoporous TiO2 layer was 39% higher.
