Influence of nitrogen-doped carbon quantum dots on titanium dioxide for photovoltaic applications: optical and structural insight

Abstract

ABSTRACT This study investigates the optical and structural properties of nitrogen-doped Carbon Quantum Dots (NCQDs) on Titanium dioxide (TiO2). We synthesized the NCQDs via direct pyrolysis using varying amount of nitrogen precursor. We used a UV-visible, Fluorescence and Fourier Transform Infrared spectrophotometer, X-ray diffractometer (XRD), and Scanning Electron Microscope (SEM) to probe the samples. The introduction of nitrogen enhanced the intrinsic activities and electron dynamics of the CQD films, leading to improved confinement, charge extraction, and light harvesting. The optical response of the NCQDs strongly hinged on the nitrogen doping content. Sensitizing different amounts of NCQDs on TiO2 surface reduced their bandgap energies. XRD analysis confirms the preservation of the TiO2 anatase phase nanoparticle after the introduction of NCQDs, with no substantial changes to the crystal lattice and phase purity of the resulting photoanodes, indicating the presence of NCQDs on the surface. However, the deposition of NCQDs decreased the crystallite size. SEM images show well-dispersed morphologies with non-clustered NCQDs films. NCQDs can serve as promising photosensitizers in photovoltaic devices.