We investigated the optical properties and thermal conductivity of blade-coated graphene quantum dots (GQDs)/PEDOT:PSS hybrid thin films by varying the content of GQDs. The optical properties were determined by spectroscopic ellipsometry in the range of 1.2–5.5 eV. Two dispersion models were used to analyze the optical properties of the films: the Bruggeman effective medium approximation (BEMA) for the hybrid films, and the Drude model combined with a Lorentzian oscillator for both the pure and the hybrid films, which provides insight into their electrical properties. As a novel finding, we observed that the optical anisotropy of PEDOT:PSS (Aldrich 483095) films is reduced after incorporating GQDs. Moreover, dedoping of the PEDOT chains is demonstrated upon increasing the content of GQDs within the hybrid films. Furthermore, the thermal conductivity shows a two-fold decrease as the GQDs fraction increases from 0 to 10 wt%. This result is understood considering that the GQDs act as local scattering centers, resulting in a decrease of the thermal conductivity.

The authors acknowledge funding from the Spanish Ministerio de Ciencia e Innovación (MICINN) through grants PDC2021-121475-I00 and PID2020-119777GB-I00 and the Spanish Severo Ochoa Centre of Excellence program CEX2019-000917-S and CEX2023-001263-S , as well as AGAUR, Generalitat de Catalunya, Spain, grant 2021-SGR-00444 . M.K. is grateful to the UAB PhD program in Materials Science in which she was enrolled and the China Scholarship Council for funding ( CSC 201809370071 ). M.K. is sincerely thankful to Bernhard Dörling and Denise Estrada-Wiese for their corrections to the English and helpful comments. We thank Agustín Mihi and Mariano Campoy-Quiles for their constant support and ideas. We acknowledge the assistance of the ICMAB-CSIC Scientific & Technical Services: Nanoquim Platform, Scanning Probe Microscopy, Electron Microscopy, and X-ray Diffraction.

With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).

Peer reviewed