Photo-Current Enhancement in Carbon Quantum Dots Functionalized Titania Nanotube Arrays

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Vertically aligned titanium dioxide (TiO2) nanotube arrays are fabricated using electrochemical anodization.
• Carbon quantum dots (CQDs) are synthesized via electrochemical reduction.
• Functionalization of TiO2 nanotubes with CQDs is explored for enhanced photo-electrochemical properties.

Purpose of the Study:

• To investigate the photo-electrochemical properties of TiO2 nanotube array-CQD composite materials.
• To compare the performance of functionalized nanotubes with pristine TiO2 nanotubes.
• To understand the impact of CQD synthesis conditions on material properties.

Main Methods:

• Characterization of TiO2 nanotubes using X-ray diffraction and scanning electron microscopy.
• Characterization of CQDs using transmission electron microscopy and optical absorption spectroscopy.
• Photo-electrochemical measurements including photocurrent, incident photon to current conversion efficiency (IPCE), Mott-Schottky plots, and impedance analysis.

Main Results:

• TiO2 nanotube array-CQD composites exhibited significantly enhanced photo-electrochemical properties compared to bare TiO2 nanotubes.
• A 30% improvement in photocurrent was observed in TiO2-CQD samples.
• Higher photo-conversion efficiency with a shift towards visible wavelengths was achieved, alongside a shift in flat-band potential and reduced charge transfer resistance.

Conclusions:

• The functionalization of TiO2 nanotube arrays with CQDs substantially improves their photo-electrochemical performance.
• The composite material demonstrates potential for applications requiring efficient light harvesting and charge transfer.
• CQD synthesis conditions influence material properties, affecting absorption spectra and performance.