Figure 6. Effect of the hole traps in the defective TiO₂ on the long-term stability of the planar heterojunction PSC.

(a) Photoelectrochemical oxidation of methylamine in water using as-deposited (orange line) and post-annealed (blue line) TiO₂ on FTO glass as photoanodes. The JV curves were measured under chopped simulated sunlight (AM 1.5G) and anodic scan at a rate of 10 mV s⁻¹. (b) Long-term stability of the planar heterojunction perovskite solar cell fabricated using as-deposited (orange line) and post-annealed (blue line) TiO₂ thin film as the ETL. The curves were measured at a bias of 0.8 V under AM 1.5G in N₂ atmosphere. The dashed line indicates a PCE of 15%.