Air-stable inverted organic solar cells using TiO2 layer deposited by atomic layer deposition

We investigated the air-stable and highly efficient inverted organic solar cells (IOSCs) using TiO₂ as electron selective layer prepared by an atomic layer deposition (ALD) method. Various thicknesses of TiO₂ layer from 10 to 50 nm were adapted to confirm the thickness effect on device performance and stability. The IOSC with 20-nm-thick TiO₂ layer showed the PCE of 3.01 % under AM 1.5 simulated illumination. Furthermore, the IOSCs showed better stability retaining over 80 % of the maximum PCE after 30 days. This suggests that IOSCs with TiO₂ layer deposited by ALD gives a promising way for fabrication of air-stable organic solar cells.