Tuning the thermal and optoelectronic properties of sol-gel derived CeO2-graphene/PMMA nanocomposites

Poly(methyl methacrylate) (PMMA) is widely used in optical applications; however, its limited thermal stability and moderate optoelectronic performance constrain its functionality in advanced devices. In this work, cerium oxide–graphene (CeO 2 –G) hybrid nanoparticles were synthesized via a sol–gel method and incorporated into PMMA films using a solution casting technique. Structural analyses indicated a reduction in the crystalline nature of PMMA due to interfacial interactions between the polymer matrix and CeO 2 –G nanofillers. Thermal analysis showed improved thermal stability with increasing filler content. Optical investigations revealed a systematic decrease in the direct and indirect bandgap energies from 6.02 to 4.38 eV and from 5.37 to 3.88 eV, respectively. Dielectric measurements demonstrated enhanced dielectric constant and AC conductivity, attributed to interfacial polarization and improved charge carrier transport. The nonlinear optical parameters were also found to increase with CeO 2 –G loading. These results demonstrate that incorporating CeO 2 –G hybrid nanoparticles provides an effective approach to tailoring the thermal, optical, and dielectric properties of PMMA for optoelectronic and related applications.