1：Experimental Design and Method Selection

Three different strategies were employed to enhance the refractive index of polystyrene thin films: incorporating cerium oxide nanoparticles onto the polystyrene matrix, adding cerium oxide nanoparticles onto the cross-linkable polystyrene, and embedding functionalized cerium oxide nanoparticles onto the cross-linkable polystyrene.

2：Sample Selection and Data Sources

Polystyrene thin films were prepared using spin coating. Cerium oxide nanoparticles were incorporated into the polystyrene matrix through various methods.

3：List of Experimental Equipment and Materials

Polystyrene (P10447-S), azide terminated polystyrene, hydrogen peroxide (H2O2), sulphuric acid (H2SO4), hydrofluoric acid (HF), cerium oxide (CeO2) nanoparticles, spin coating machine (SPS Spin 150i), spectroscopic ellipsometer (Horiba Jobin Yvon, UVISEL instrument), Atomic Force Microscope (Multimode, NanoscopeIIIa).

4：Experimental Procedures and Operational Workflow

Preparation of neat polystyrene thin films, cerium oxide nanoparticle decorated polystyrene thin films, cross-linked polystyrene–cerium oxide nanoparticle thin films, and cross-linked polystyrene-embedded with modified ceria oxide nanoparticle thin films. Characterization was done using ellipsometry and AFM.

5：Data Analysis Methods

Refractive index and thickness of the thin films were measured using ellipsometry. AFM was used to understand the morphology of the thin films.