Study on Perovskite Photo-sensors with Solution-Processed Compact TiO2 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.