PEDOT:PSS, TiO2 Nanoparticles, and Carbon Quantum Dot Composites as Ultraviolet Sensors

In this study, we have established an efficient method to develop a solution-processed ultraviolet (UV) sensor with easy fabrication, a high response, and cost-effectiveness. Aiming at this, we developed a platform to utilize the synergistic effect of a hybrid network comprising a conducting polymer poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and inorganic and organic UV sensitive materials, titanium dioxide (TiO2) nanoparticles and carbon quantum dots (CQDs):TiO2 nanocomposites, respectively. With the addition of the organic solvent dimethyl sulfoxide (DMSO) to the nanocomposites, the structural architecture of the hybrid film was altered, leading to the enhancement of the overall responsivity and conductivity of the sensor. The structural modifications in the hybrid film were confirmed through Raman spectroscopy, whereby peak shifts were detected. The hybrid film was fabricated on the silicon wafer (p-type) by using a simple drop-cast technique. Upon the illumination of UV radiation on the hybrid film, the change in conductivity was measured for light and dark modes. The proposed sensors demonstrated responsivity of 48.6% and response and recovery times of 235 and 360 s, respectively, for UV on/off cycles, which was substantially greater than that of the pristine PEDOT:PSS films, whose responsivity was 7.27% and response and recovery times of 753 and 856 s, respectively. The proposed sensor can be used in UV sensing applications for the detection of skin cancer, premature aging, and several other UV-induced skin ailments.