High-Efficiency Perovskite Solar Cells Treated by Rutile TiO2 Nanoparticles (<4 nm) from Ti3C2 MXene Oxidation

Research on perovskite solar cells has gradually pushed them toward commercial fabrication, and considering the wide range of solar cell applications, it is still interesting to have diverse compositions of devices. The electron transport layer of the perovskite solar cells prepared by the conventional spin-coating method inevitably has many defects, which obviously affect the interface contact and carrier transport performance. Rutile TiO2 nanoparticles with an average size of 2.1 nm used as part of the electron transport layer are obtained by oxidation of Ti3C2 MXene for the first time. A series of test results show that the rutile TiO2 nanoparticles obtained in this way are obviously beneficial to the performance of the device, especially in suppressing the hysteresis effect. A champion power conversion efficiency of 21.55% with a hysteresis index of 0.047 is achieved, which is much better than 19.18% and 0.115 of the control device. This work provides enlightening viewpoints for the application of two-dimensional MXene materials and a new synthetic route in the field of perovskite solar cells.