Thermally Stable Perovskite Solar Cells by All-Vacuum Deposition.

Area of Science:

• Materials Science
• Renewable Energy
• Semiconductor Physics

Background:

• Vacuum deposition offers a solvent-free route for metal halide perovskite (MHP) thin film growth.
• Current high-efficiency MHP solar cells often rely on solution-processed hole transport layers (HTLs), hindering industrial scalability and stability.
• Developing stable, vacuum-compatible HTLs is crucial for advancing MHP solar cell technology.

Purpose of the Study:

• To investigate organometallic copper phthalocyanine (CuPc) and zinc phthalocyanine (ZnPc) as alternative HTLs for all-vacuum-deposited MHP solar cells.
• To evaluate the performance and stability of MHP solar cells utilizing CuPc and ZnPc HTLs.
• To enable solvent-free, scalable fabrication of efficient and durable perovskite solar cells.

Main Methods:

• Fabrication of formamidinium-cesium lead triodide [CH(NH2)2]0.83Cs0.17PbI3 (FACsPbI3) perovskite solar cells using vacuum deposition.
• Incorporation of organometallic CuPc and ZnPc as hole transport layers (HTLs) in an inverted p-i-n configuration.
• Performance characterization including power conversion efficiency (PCE) measurements.
• Long-term stability testing under ambient storage and thermal stress conditions.

Main Results:

• The CuPc HTL, in an inverted p-i-n solar cell configuration, achieved a power conversion efficiency (PCE) of up to 13.9%.
• All-vacuum-deposited, solvent-free FACsPbI3 perovskite solar cells with CuPc HTLs demonstrated remarkable long-term stability.
• Unencapsulated 1 cm2 devices showed no degradation after over 5000 hours of storage and 3700 hours of thermal stress at 85 °C in N2.

Conclusions:

• Organometallic CuPc serves as a viable, low-cost, and durable HTL for all-vacuum-deposited perovskite solar cells.
• The use of CuPc HTLs facilitates a completely solvent-free fabrication process, enhancing prospects for industrial upscaling.
• These findings pave the way for highly stable and efficient perovskite solar cells manufactured via scalable vacuum deposition techniques.