Improved Perovskite Solar Cell Performance by High Growth Rate Spatial Atomic Layer Deposited Titanium Oxide Compact Layer

In this study, titanium dioxide (TiO
₂
) films are prepared using spatial atomic layer deposition (sALD) as an additional compact layer of tin oxide (SnO
₂
) electronic transport layer-based perovskite solar cells. The experimental results show that the deposition of sALD TiO
₂
films on the fluorine-doped tin oxide substrate improves the haze at mid-long wavelengths, compensating the optical loss caused by the absorption of the TiO
₂
layer in short-wavelengths. Compared to conventional cells, the insertion of the sALD TiO
₂
compact layer regardless the thickness shows significantly improved open-circuit voltage, indicating the enhanced hole blocking ability as evidenced by the reduced reverse saturation current. In addition, the change in TiO
₂
thickness is found to have impacts on short-circuit current, fill factor and hysteresis of the devices. The optimal sALD TiO
₂
thickness of 10 nm leads to the best cell conversion efficiency of 20.1%, approximately improved by 6% compared to that of the conventional cells. Compared to conventional ALD techniques and other methods, the sALD which does not require vacuum system has the pinhole-free, low-cost, very fast and simple processes, demonstrating the great potential of sALD films for applications in perovskite solar cells.