Study on Perovskite Photo-sensors with Solution-Processed Compact TiO 2 Under Low Temperature Fabrication Process

We have investigated a perovskite photo-sensors with solution-processed compact TiO 2 under low temperature process. The TiO 2 films was grown from an aqueous solution of titanium tetrachloride (TiCl 4 ) at 70°C by chemical bath deposition method. Then, the perovskite layer was deposited on the TiO 2 layer by the two-step method in the glovebox under an N2 environment. Next, the hole transport layer of Spiro-OMeTAD solution was spin-coated. The device structure was FTO/ TiO 2 / perovskite layer/ Spiro-OMeTAD/Au. For the sensing characteristics, a ratio of photo- and dark-current was 6.3×10 ³ . This value was little higher than that of the previous study with EB-evaporated TiO 2 layer.