Reductive contact and dipolar interface engineering enable stable flexible CsSnI₃ nanowire photodetectors

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Lead-free tin-based halide perovskites offer potential for flexible and eco-friendly optoelectronics.
• Key limitations include rapid Sn²⁺ oxidation to Sn⁴⁺ and poor operational stability.

Purpose of the Study:

• To develop a stable and high-performance flexible CsSnI₃ nanowire photodetector.
• To address the instability issues of tin-based perovskites through substrate and interface engineering.

Main Methods:

• Utilized anodized aluminum foil as a flexible substrate with laser-ablated metallic aluminum regions acting as reductive sites.
• Incorporated a 3-fluoro-2-nitroanisole (3F-2NA) polar interlayer for energy-level alignment and charge extraction enhancement.
• Fabricated flexible CsSnI₃ nanowire photodetectors.

Main Results:

• Achieved high near-infrared photoresponse with responsivity of 0.39 A W^-1 and specific detectivity of 1.38 × 10¹³ Jones.
• Demonstrated a wide linear dynamic range of 156 dB at 850 nm illumination.
• Exhibited excellent long-term stability, retaining over 85% photocurrent after 60 days and 94% after 1000 bending cycles.

Conclusions:

• Synergistic aluminum-substrate contact engineering and dipolar interface modification effectively stabilize tin-based perovskites.
• The developed strategy enables high-performance flexible optoelectronic devices with enhanced operational stability.