Low temperature TiOx compact layer by chemical bath deposition method for vapor deposited perovskite solar cells

In this paper, we try to fabricate the planer heterojunction (PHJ) perovskite solar cell based on low temperature TiOx compact layer by chemical bath deposition (CBD) method. We compared solar cell properties between compact-TiO_x layer and compact-TiO₂ layer, where CBD deposited films were heated at 250 °C in order to convert into TiO_x amorphous state and 450 °C intoTiO₂ anatase state, respectively. Power conversion efficiency of PHJ perovskite solar cell based on our compact-TiO_x shows almost same as that of TiO₂ one. In addition, we discuss the origin of hysteresis of PHJ perovskite solar cell based on compact-TiO_x and TiO₂. We conclude that hysteresis of PHJ perovskite solar cell is heavily influenced by surface coverage and roughness of compact-TiO_x or TiO₂ layers on transparent conducting oxide.