One-Dimensional Organic Lead Bromide Elastic Crystals with Strong Electron-Phonon Coupling

Area of Science:

• Materials Science
• Solid-State Chemistry
• Crystallography

Background:

• One-dimensional (1D) coordination polymers are of interest for their unique electronic and optical properties.
• Lead halide materials offer tunable optoelectronic characteristics.
• Developing materials with enhanced elasticity and specific photoluminescence is crucial for advanced optical devices.

Purpose of the Study:

• To synthesize and characterize novel 1D lead halide elastic crystals.
• To investigate the relationship between elasticity and photoluminescence properties.
• To explore the potential applications of these materials in optoelectronics.

Main Methods:

• Single-crystal X-ray diffraction for structural determination.
• Mechanical testing to evaluate bending strain.
• Variable-temperature fluorescence spectroscopy to study emission properties.

Main Results:

• Two novel 1D compounds, [Pb2Br4(DMA)2] (1) and [Pb2Br4(DMF)2] (2), were synthesized.
• Compound 1 demonstrated a bending strain of 1.36%, surpassing previously reported 1D single-metal axis polymers.
• Compound 1 exhibited strong red-to-NIR fluorescence below 200 K (peak at 700 nm, fwhm of 200 nm), indicative of strong electron-phonon coupling and large Stokes shift attributed to its elasticity.

Conclusions:

• The synthesized 1D bimetallic axis chain lead halide crystals possess superior elastic properties.
• The inherent elasticity of compound 1 significantly influences its photoluminescence, leading to a large Stokes shift and broad emission.
• These 1D organic lead halide elastic crystals are promising candidates for applications in NIR light-emitting diodes, supercontinuum sources, and flexible optical waveguides.