Rapid, low-temperature, air plasma sintering of mesoporous titania electron transporting layers in perovskite solar cells

Reducing the sintering temperature and time of mesoporous titanium dioxide (m-TiO2) from the standard thermal approach of baking at 500 °C for 1 h is an important step for employment of mesoscopic perovskite solar cells (PSCs). We present a robust method based on atmospheric pressure ambient air plasma of the diffuse coplanar surface barrier discharge (DCSBD) for sintering of m-TiO2 in 2.5 min at 70 °C. When implemented in PSCs as an electron transport layer an efficiency of (15.8 ± 1.0) % was achieved, which is on the same level as a standard thermal approach. The organic moieties which hinder the perovskite infiltration into the porous structure were removed to a similar extent as the thermal sintering. The approach does not affect the conduction band alignment with the perovskite absorber and an appropriate energy offset is preserved.