Pb2B5O9I: an iodide borate with strong second harmonic generation.

Area of Science:

• Materials Science
• Solid-State Chemistry
• Nonlinear Optics

Background:

• Borate materials are crucial for nonlinear optics.
• Developing new borates with enhanced properties is an ongoing research area.
• Phase-matchable materials with high second-harmonic generation (SHG) are highly sought after.

Purpose of the Study:

• To synthesize and characterize a novel pentaborate material, Pb(2)B(5)O(9)I.
• To investigate the origin of its nonlinear optical properties.
• To evaluate its potential for optical applications.

Main Methods:

• Synthesis of Pb(2)B(5)O(9)I.
• Powder SHG measurements.
• UV-Vis-NIR transmission spectroscopy.
• Density Functional Theory (DFT) calculations.

Main Results:

• Pb(2)B(5)O(9)I was successfully synthesized.
• It exhibits the largest powder SHG response among known borates (approx. 13.5 times that of KDP).
• The material shows transparency from the near-UV to the middle-IR region.
• DFT calculations confirmed the roles of Pb(2+) lone-pair electrons and I(-) electronegativity in the observed SHG properties.

Conclusions:

• Pb(2)B(5)O(9)I is a promising phase-matchable nonlinear optical material.
• Its unique structure and electronic properties lead to exceptional SHG performance.
• The findings provide insights into the design principles for advanced borate-based optical materials.