“…The reason for surpassing the PCE of commercially available silicon-based devices in such a short time is the understanding of the perovskite material, which has high carrier mobilities and long exciton charge diffusion length associated with long carrier lifetimes, tunable band gap, and high absorption extinction coefficient. , The PSCs are mainly structured as regular (n–i–p) and inverted (p–i–n), according to the position of the charge transport layers. For instance, in regular PSC configuration, the widely reported, n-type metal oxides, such as SnO 2 , TiO 2 , and ZnO, are deposited between the bottom electrode and the perovskite absorber layer due to their highly electron-selective properties. , However, high processing temperatures (∼450 °C) are required to induce the crystallization of these metal oxides, which significantly increases the production cost of these devices. Moreover, while this requirement makes it impossible to manufacture solar cells on flexible substrates, it is also a non-negligible obstacle for large-scale commercial device production methods in the roll-to-roll process. , Even though inverted PSCs have lower device performance than regular PSCs, they are prepared with a lower processing temperature (∼100 °C) that allows them to be deposited onto flexible and large-scale substrates.…”