**4.1 Perovskite (PVSK) film processing**

There are several methods in the fabrication of perovskite (PVSK) films employed as active layers in solar cells; e.g. spin coating, dip coating, gas-quenching (GQ), thermal co-evaporation or vapor phase conversion. Of all these methods, spin coating is most preferred, since it can control the production of consistent films with high quality when compared with the other techniques. It is easy to realize PVSK films on a flat substrate using the above methods generally. For textured substrate however the challenge remains, when using solution-processed spin coating. Consequently a combination of sequential co-evaporation and spin-coating was developed as a hybrid two-step deposition method. That forms a conformal PVSK layer on the micro-size pyramids of textured mono-crystalline silicon.
