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The TiO 2 nanorod arrays with the length of 70 nm, the diameter of 20 nm, and the areal density of 1000 µm −2 were firstly prepared by the hydrothermal method using the aqueous grown solution of 38 mM titanium isopropoxide and 6 M hydrochloric acid at 170 °C for 60 min. Over-500 nm-thickness CH 3 NH 3 PbI 3−x Br x absorber layers were successfully obtained by sequential deposition routes using 1.7 M PbI 2 ·DMSO complex precursor solution and 0.465 M isopropanol solution of the methylammonium halide mixture with the molar ratio of CH 3 NH 3 I/CH 3 NH 3 Br=85/15. The perovskite solar cells based on the TiO 2 nanorod array and 560 nm-thickness CH 3 NH 3 PbI 3−x Br x absorber layer exhibited the best photoelectric conversion efficiency (PCE) of 15.93%, while the corresponding planar perovskite solar cells without the TiO 2 nanorod array and with 530 nm-thickness CH 3 NH 3 PbI 3−x Br x absorber layer gave the best PCE of 12.82% at the relative humidity of 50–54%. [ABSTRACT FROM AUTHOR]