Bilayer-Assisted Substrate Engineering for Fully Vacuum-Deposited CsPbI₂Br Perovskite Photodetectors

Area of Science:

• Materials Science
• Optoelectronics
• Solid-State Physics

Background:

• All-inorganic metal halide perovskites show promise for visible light detection but face challenges in scalable, continuous fabrication for high-quality films and device stability.
• Existing fabrication methods often involve solution processing, limiting scalability and uniformity.

Purpose of the Study:

• To report a novel, fully vacuum-based, continuous deposition process for fabricating all-inorganic perovskite photodetectors (PDs).
• To demonstrate the high performance and stability of these PDs for optoelectronic applications.
• To validate the integration of these PDs into a functional system, such as Li-Fi.

Main Methods:

• Fabrication of CsPbI2Br PDs using a fully vacuum-based, continuous deposition process on a bilayer-engineered substrate.
• Characterization of PD performance, including dark current density, specific detectivity (D*), response time, linear dynamic range, and cutoff frequency.
• Assessment of long-term operational stability under continuous illumination.
• Integration of the PD into a Light Fidelity (Li-Fi) system to test data transmission capabilities.

Main Results:

• Achieved a low dark current density of 9.2 × 10^-10 A cm^-2 and a high specific detectivity (D*) of 2.0 × 10^13 Jones.
• Demonstrated a fast response time of approximately 2 μs, a linear dynamic range of 109 dB, and a cutoff frequency exceeding 300 kHz.
• The device retained 70% of its initial photocurrent after 30 days of continuous illumination, indicating robust stability.
• Successfully validated data transmission capability by integrating the PD into a functional Li-Fi system.

Conclusions:

• The fully vacuum-deposited, continuous fabrication strategy offers a scalable and stable approach for all-inorganic perovskite PDs.
• The demonstrated high performance and stability make these PDs suitable for high-speed optoelectronic applications, including optical communication.
• The fabrication process is compatible with existing OLED manufacturing, paving the way for industrial integration.