Characterization of Perovskite Solar Cells According to TiO₂ Mesoporous Layer Treated with Ti-Diisopropoxide Bis

The power conversion efficiency of perovskite solar cells, which are next-generation photovoltaic cells, has rapidly increased up to 20% through ongoing research and development. Recently, various methods have been employed to increase the active area of the mesoporous layer in perovskite solar cells. In this study, the particle aggregation of the TiO₂ was controlled by adding Ti-diisopropoxide bis to the mesoporous layer solution; thus, the contact area between the mesoporous layer and perovskite layer was increased. The amount of Ti-diisopropoxide bis added to the mesoporous layer solution was adjusted to prevent the inhibition of electron transport caused by separation of particles and instability of mesoporous layer. To evaluate the changes in the characteristics of the perovskite solar cells due to the TiO₂ particle aggregation in the mesoporous layer, X-ray diffraction and spectrophotometric absorbance, as well as cross-sectional and surface scanning electron microscopy measurement were performed, and the current density-voltage curve, power conversion efficiency and other properties were evaluated under solar simulator. It was found that the mesoporous layer was improved due to its enlarged contact area, and hence, can be expected to improve the efficiency of perovskite solar cells.