1：Experimental Design and Method Selection:

The study employs CsPbBr3 perovskite nanowires to modify the surface electronic states of bulk perovskite thin films, forming a compositionally-graded heterojunction at the perovskite/HTL interface of PSCs. The nanowire morphology is key to achieving lateral homogeneity in the perovskite film surface states.

2：Sample Selection and Data Sources:

CsPbBr3 perovskite nanocubes (NCs) and nanowires (NWs) were synthesized using modified methods reported in the literature.

3：List of Experimental Equipment and Materials:

Transmission electron microscope (TEM), UV–vis absorption and photoluminescence (PL) spectra, X-ray diffraction (XRD) patterns, scanning electron microscope (SEM), atomic force microscopy (AFM), Kelvin-probe force microscopy (KPFM), and glancing-angle XRD analysis.

4：Experimental Procedures and Operational Workflow:

The as-synthesized CsPbBr3 NCs or NWs were dispersed in chlorobenzene, forming colloidal suspension for use in the thin film processing. The processing method involves spin-coating and thermal annealing to 'fuse' the CsPbBr3 NCs or NWs into the perovskite thin film via diffusion.

5：Data Analysis Methods:

The study analyzes the morphology, surface potential, and depth profile of the CsPbBr3 nanocrystals incorporation, and evaluates the performance and stability of the PSC devices.