Spatially Resolved Anion Diffusion and Tunable Waveguides in Bismuth Halide Perovskites

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Bismuth halide perovskites are explored as lead-free alternatives in optoelectronics and solar energy.
• Their tunable composition and optical properties make them suitable for photonic devices.
• Controlling anion composition in these perovskites has been a significant challenge.

Purpose of the Study:

• To develop robust protocols for synthesizing bismuth halide perovskite nanoflakes with controlled dimensions and compositions.
• To investigate the influence of anion composition and flake thickness on optical properties.
• To demonstrate gradient anion distribution for novel device applications.

Main Methods:

• Chemical vapor deposition (CVD) for nanoflakes synthesis.
• Anion exchange protocols to control halide composition.
• Time-of-flight secondary ion mass spectrometry (ToF-SIMS) for spatial resolution of anion distribution.

Main Results:

• Successful synthesis of bismuth halide perovskite nanoflakes with controlled dimensions and variable compositions.
• Demonstration of gradient bromide distribution achieved through controlled anion exchange and diffusion.
• Modulation of optical waveguiding properties by varying flake thickness and anion composition.

Conclusions:

• Established chemical vapor deposition and anion exchange protocols offer robust control over bismuth halide perovskite nanoflakes.
• Gradient anion distribution and tunable optical properties open new avenues for optoelectronic devices and integrated photonics.
• Bismuth halide perovskites present a promising, nontoxic platform for advanced photonic applications.