1：Experimental Design and Method Selection:

The study involved the incorporation of the pseudohalide ion SCN(cid:2) into CsPbI3 thin films by adding lead thiocyanate (Pb(SCN)2) to the CsPbI3 precursor solution. The methodology aimed to achieve larger-sized crystals and fewer trapped CsPbI3 films.

2：Sample Selection and Data Sources:

CsPbI3 thin films were fabricated with different concentrations of the Pb(SCN)2 additive: 0%, 1%, 2%, and 4%. The films were characterized using XRD, PL, SEM, AFM, XPS, and UV-vis absorption spectra.

3：4%. The films were characterized using XRD, PL, SEM, AFM, XPS, and UV-vis absorption spectra. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment included XRD for phase structure analysis, SEM and AFM for surface morphology, XPS for surface elemental distributions, and UV-vis for absorption spectra. Materials included CsI, DMAPbI3, PbBr2, Pb(SCN)2, DMF, DMSO, PTAA, Li-TFSI, TBP, and CB solution.

4：Experimental Procedures and Operational Workflow:

The CsPbI3 precursor solution was prepared and spin-coated on TiO2/FTO/glass substrates, followed by annealing. The PTAA solution was then spin-coated onto the perovskite films, and a gold top electrode was thermally evaporated.

5：Data Analysis Methods:

The data were analyzed to assess the crystallinity, surface morphology, elemental distribution, and optical properties of the films, as well as the photovoltaic performance of the devices.