Figure 5. Effect of the hole traps in the defective TiO₂ on the photocurrent of planar heterojunction PSC.

(a) Evolution of the photocurrent from a complete PSC under full AM 1.5G spectrum (orange line) and visible light (blue line) illumination. The curves were measured at a bias of 0.8 V and a 425 nm-long pass filter was used to block the ultraviolet light. The devices were not subjected to any illumination before the test. (b) Charge trapping and de-trapping process revealed in complete PSCs by repeatedly applying and removing the ultraviolet filter. The curve was measured at a bias of 0.85 V after light soaking for about 30 min. Grey colour: in the dark, purple colour: under full AM 1.5G illumination, green colour: under visible illumination.