Microstructural analysis and thermoelectric performance of Ga-doped ZnO/reduced graphene oxide thin film nanocomposites

In this work, n-type Ga-doped ZnO (GZO)/reduced graphene oxide (rGO) thin-film nanocomposites were investigated as an approach to enhancing the electron transport of a popular material having weak thermoelectric properties. Namely, the rGO contents of 1, 3, 5, and 7 wt% were mixed in the matrix of chemically derived GZO. The XRD, Raman, XPS spectroscopies, and SEM mapping indicated and confirmed the presence of rGO in the thin-film nanocomposites having good density, nanoscale grains, and stoichiometry of elements in the composition. In this case, rGO sheets enclosed in the grain boundaries of polycrystalline GZO behaved as bridge, which facilitated electron transport and effectively improved the thermoelectric performance of the film nanocomposites. Consequently, the magnitude of the electrical conductivity and power factor of the samples increased by four to five times larger than those of rGO-free GZO ones in the range from room temperature to 400 degrees C. The obtained results provide promising perspectives of a binary composite material made of environmentally benign, earth-abundant elements, and fabricated by a simple and low-cost process for thermoelectric applications.

Automated summary

The study investigated n-type GZO/rGO thin-film nanocomposites, where rGO acted as a bridge to improve electron transport and enhance thermoelectric performance. The electrical conductivity and power factor of the samples increased by four to five times compared to rGO-free samples, showing promising potential for applications.