Fabrication of Fully Solution Processed Inorganic Nanocrystal Photovoltaic Devices

Area of Science:

• Materials Science
• Nanotechnology
• Renewable Energy

Background:

• Solution-processed inorganic solar cells offer a promising alternative to traditional photovoltaic technologies.
• Nanocrystal inks provide a versatile route for fabricating thin-film solar cells with tunable properties.

Purpose of the Study:

• To develop a fully solution-processed method for inorganic solar cells using spin and spray coating of nanocrystal inks.
• To investigate the effects of various chemical and physical treatments on the performance of cadmium chalcogenide-based solar cells.

Main Methods:

• Synthesis of colloidal cadmium telluride (CdTe), cadmium selenide (CdSe), and gold (Au) nanocrystals.
• Deposition of indium tin oxide (ITO), CdSe, CdTe, and Au layers via spin and spray coating.
• Ligand exchange using ammonium chloride (NH4Cl) and thermal annealing at 200-400 °C.
• Characterization using SEM, optical profilometry, FTIR, XRD, UV/Vis spectroscopy, and current-voltage measurements.

Main Results:

• Successful fabrication of glass/ITO/CdSe/CdTe/Au nanocrystal solar cells.
• NH4Cl as an effective and non-toxic sintering catalyst, promoting grain growth (136±39 nm).
• Observed red shift in absorbance of cadmium chalcogenide nanocrystals post-annealing.
• Demonstrated significant influence of deposition techniques and ligand exchange reagents on device performance.

Conclusions:

• The developed method enables the preparation of fully solution-processed inorganic solar cells.
• Optimization of chemical treatments (ligand exchange, sintering agents) and physical parameters is crucial for enhancing photovoltaic device performance.
• This work provides insights into controlling nanocrystal film properties for efficient solar energy conversion.