Rare-earth-incorporated ternary Ce Cd_1- S quantum dot-sensitized solar cells

Area of Science:

• Materials Science
• Nanotechnology
• Photovoltaics

Background:

• Solar cell efficiency is limited by absorber material properties.
• Ternary quantum dots offer tunable optoelectronic properties.
• Rare-earth doping in quantum dots is an emerging area for photovoltaic applications.

Purpose of the Study:

• To synthesize and characterize novel cerium-doped cadmium sulfide (Ce-CdS) quantum dots (QDs).
• To investigate the effect of cerium doping on the structural and optical properties of CdS QDs.
• To evaluate the photovoltaic performance of solar cells fabricated with Ce-CdS QDs.

Main Methods:

• Two-step solution processing for synthesizing Ce-CdS QDs on a mesoporous TiO2 electrode.
• Post-annealing treatment to form the ternary Ce-CdS structure.
• Fabrication of quantum dot solar cells (QDSCs) using a polysulfide electrolyte and CuS counter electrode.

Main Results:

• Synthesized Ce-CdS QDs exhibit a hexagonal structure with tunable band gaps (2.40–2.24 eV) controlled by Ce content.
• The best performing Ce-CdS QDSC achieved an efficiency of 3.72% under 1 sun, a 25% improvement over host CdS cells.
• Increased efficiency was observed under reduced light intensity (4.24% at 0.25 sun), attributed to broader light absorption.

Conclusions:

• Cerium doping effectively tunes the band gap of CdS quantum dots.
• Ce-CdS quantum dots demonstrate enhanced photovoltaic performance compared to undoped CdS.
• This study highlights the potential of rare-earth-doped CdS QDs for advanced solar cell applications.