Monolithic Integration of Redox-Stable Sn-Pb Halide Perovskite Single-Crystalline Films for Durable Near-Infrared...

Area of Science:

• Materials Science
• Optoelectronics
• Crystallography

Background:

• Tin-lead (Sn-Pb) halide perovskites are promising for near-infrared (NIR) optoelectronics due to their narrow bandgaps and long carrier diffusion lengths.
• Conventional growth methods involve high temperatures, leading to issues like Sn²⁺ oxidation and poor integration with planar devices.

Purpose of the Study:

• To develop a low-temperature crystallization strategy for Sn-Pb perovskite single-crystal thin films.
• To enable direct growth on device-compatible substrates for improved optoelectronic applications.

Main Methods:

• A coordination-engineered crystallization strategy using a low-donor number cosolvent system was employed.
• This method modulates metal-solvent coordination to stabilize precursors and guide crystal growth at mild temperatures (<40 °C).

Main Results:

• Micrometer-thick, smooth, and highly crystalline Sn-Pb single-crystal films with uniform composition and ultralow trap densities (~3.98 × 10¹² cm^-3 were achieved.
• NIR photodetectors fabricated with these films demonstrated high responsivity (0.51 A/W at 900 nm), detectivity (3.6 × 10¹² Jones), and fast response (~188 μs).
• The films exhibited over 25,000 cycles of ambient operational stability.

Conclusions:

• The coordination-engineered approach enables scalable, low-temperature growth of redox-stable Sn-Pb perovskite crystal films.
• This work expands the processing-structure-function relationships for advanced infrared optoelectronics.