A solid-state CdSe quantum dot sensitized solar cell based on a quaterthiophene as a hole transporting material

Area of Science:

• Materials Science
• Nanotechnology
• Renewable Energy

Background:

• Quantum dot sensitized solar cells (QDSCs) offer a promising avenue for photovoltaic applications.
• Developing efficient solid-state QDSCs processed in air remains a key challenge.
• Titanium dioxide (TiO2) and organic hole conductors are common components in QDSC architectures.

Purpose of the Study:

• To fabricate and characterize a hybrid solid-state quantum dot sensitized solar cell (QDSC) using CdSe quantum dots (QDs).
• To investigate the effect of QD attachment methods on device performance.
• To optimize the device through thermal annealing for improved efficiency.

Main Methods:

• Fabrication of a hybrid QDSC using CdSe QDs, TiO2 electron conductor, and 3,3'''-didodecyl-quaterthiophene (QT12) hole conductor.
• Introduction of QDs into the TiO2 layer via successive ionic layer adsorption and reaction (SILAR) or direct/linked colloidal QD attachment.
• Post-fabrication thermal annealing to enhance device performance.

Main Results:

• The method of QD attachment significantly impacts device efficiency, with direct adsorption yielding the best outcomes.
• The fabricated solid-state QDSCs achieved remarkable open circuit potentials close to 1 V.
• An initial power conversion efficiency of 0.34% (AM 1.5G) was recorded, representing a high value for TiO2-based solid-state QDSCs with colloidal QDs.

Conclusions:

• Direct adsorption of CdSe QDs onto TiO2 is an effective strategy for solid-state QDSC fabrication.
• Thermal annealing can improve the performance of these devices.
• The developed solid-state QDSCs demonstrate potential, achieving competitive efficiencies within their class.