High Efficiency Mesoscopic Solar Cells Using CsPbI₃ Perovskite Quantum Dots Enabled by Chemical Interface...

Area of Science:

• Materials Science
• Renewable Energy
• Nanotechnology

Background:

• All-inorganic cesium lead iodide perovskite quantum dots (α-CsPbI₃ QDs) offer enhanced stability and light harvesting for solar cells.
• Ex situ synthesized QDs reduce perovskite layer deposition variability.
• Incorporating α-CsPbI₃ QDs into mesoporous titanium dioxide (m-TiO₂) electron transport layers is challenging.

Purpose of the Study:

• To engineer the m-TiO₂ surface for improved α-CsPbI₃ QD incorporation.
• To enhance charge transfer at the m-TiO₂/QD interface.
• To improve the power conversion efficiency and reproducibility of perovskite quantum dot solar cells.

Main Methods:

• Surface engineering of m-TiO₂ using an electron-rich cesium-ion containing methyl acetate solution.
• Utilizing an ethanol-environment smoothing route to reduce surface roughness.
• Fabrication and characterization of perovskite quantum dot solar cells.

Main Results:

• Surface treatment reduced interfacial tension and improved wettability, facilitating QD migration into m-TiO₂.
• Cesium ions passivated QD surfaces and promoted charge transfer, increasing electron injection rate by a factor of 3.
• Optimized devices achieved reproducible power conversion efficiencies exceeding 13%, with the best cell reaching 14.32% efficiency and a short-circuit current density of 17.77 mA cm^-2.

Conclusions:

• Surface engineering of m-TiO₂ with cesium ions is an effective strategy for integrating α-CsPbI₃ QDs.
• The combined surface treatments significantly enhance electron injection and device performance.
• This approach leads to highly efficient and reproducible perovskite quantum dot solar cells.