A new method enables the reconstruction of frequency-dependent electrical characteristics in devices based on graphene quantum dots (GQDs) doped with CeO₂ nanoparticles, combining experimental measurements with a physics-based evaluation of the system. The technique is applied to the analysis of interface states, the electronic levels that appear at material boundaries and govern the dynamic behaviour of the device.

Interface states are a key factor in the performance of electronic and optoelectronic devices, acting as traps that capture and release charge carriers depending on the frequency of the applied signal. Their precise characterisation is challenging when the device combines nanoscale materials, such as GQDs, with functional oxides such as CeO₂ nanoparticles, whose catalytic and redox activity adds complexity to the electrical response.

The approach described uses a physics-based evaluation to validate and complement the reconstruction of the electrical characteristics, rather than relying on a purely empirical fit. This makes it possible to extract information on the distribution and dynamics of interface states from the frequency dependence of the device response.

Improved characterisation of interface states is relevant for the design of sensors, memories and devices based on carbon nanomaterials and oxides, where the interface between phases largely determines stability and switching speed.