The electrical and humidity sensing properties of the GO/TNC films were adjusted by gradually reducing GO via DUV radiation, mediated by the strong photocatalytic activity of the TNCs. The films were illuminated using a DUV radiation source (main emission wavelength of 254 nm, irradiance of 520 mW/cm 2 ) to match the absorbance of the TNCs. A detailed characterization of the lamp can be found in the Supporting Information, Section S4. The substrate-supported films were irradiated under ambient conditions (i.e., in air) using different exposure times. To avoid heating of the samples, the apparatus was continuously ventilated with fans. Figure ) shows a schematic of the proposed TNC-mediated photocatalytic reduction of GO to rGO. The image displays a representative chemical structure of GO, with both aromatic and sp 3 -hybridized regions. The basal plane of GO contains oxygencontaining functional groups, such as epoxide and hydroxy groups, while carboxy groups are predominantly present at the edges. This structure is analogous to the Lerf-Klinowski model proposed for the chemical structure of graphite oxide. Upon UV excitation, an electron-hole pair is generated in the TNCs. The photogenerated electrons can reduce the GO, partially restoring the aromatic system. Similar approaches to reduce GO have been reported in previous works where the photoreduction was carried out in the presence of ethanol as hole scavenger, leading to the accumulation of the photogenerated electrons on the titania surface to reduce the GO. As our experiments were conducted under ambient conditions, we propose that the amine ligands that stabilize the TNCs (OLAM) are oxidized and degraded during the photocatalytic reaction, as has been previously reported for OLAM-stabilized nanocomposites used in photocatalysis. For a qualitative assessment, ATR-FTIR spectra of representative drop-casted GO/TNR and GO/TNP thick films before and after DUV exposure were acquired. With increasing DUV exposure time, the intensity of the band assigned to the CH 2 stretching mode of OLAM decreased, supporting the suggested mechanism involving the oxidative degradation of the ligand as sacrificial hole scavenger. Hence, the coverge on the TNC surface with amine ligands to DUV exposure can play a role as limiting factor for the rGO formation. The FTIR spectra are provided in the Supporting Information, Section S5.