Issue 24, 2015 - Xinjiang Institute of Physics and Chemistry successfully synthesized homogeneous polycrystalline polyborate inorganic materials

Polar crystalline materials have a variety of functional properties, such as ferroelectric, pyroelectric and nonlinear optics, etc.
, and are the basic materials of optoelectronic technology, which are widely used in optoelectronics, medicine and other fields
.
The key to developing new polar crystalline materials is to understand their structure-property relationship
.
At present, the research on the structure-property relationship of polar materials mainly focuses on crystalline materials with similar or similar structures, while the research based on homogeneous polycrystalline compounds has rarely been reported
.

Homogeneous polycrystalline compounds have their unique advantages, with the same composition, different structures resulting in different functional properties, which is an ideal system
for studying the structure-property relationship of materials.
However, the research on polar functional materials of homogeneous polycrystalline currently faces two major challenges, namely, the low probability of inorganic materials crystallizing in the polar space group and how to effectively crystallize the materials in the polar space group and behave polytypic phases
.

The research team of optoelectronic functional materials of Xinjiang Institute of Physics and Chemical Technology, Chinese Academy of Sciences, introduced Zn2+ ions into the borate anionic structure framework with variable structure to increase the flexibility of the anion framework, combined with Pb2+ cations with diverse coordination environments, and synthesized homogeneous polycrystalline Pb2Ba4Zn4B14O31 compounds, which coexist in three phases, respectively crystallized in the triclinic P1, monoclinic Cc and tripartite P32, all of which belong to the polar
。 This is the first case of a borate inorganic material
in which all homogeneous polycrystalline phases are crystallized in a polar space group.
Through detailed structural comparison, researchers analyzed the influence of different structures of materials on the functional properties of polar materials, and enriched the relationship between
structure and properties of polar materials.
At the same time, researchers also calculated and analyzed the structure-performance relationship
in the polar crystal structure based on first principles.
This study also shows that the use of coordinated cations with diverse coordination and increased anionic structural framework flexibility are effective ways to
design and synthesize polar polytypes.

The research results were published in Chem.
Mater.
, related research work has been funded
by the National Outstanding Youth Fund, the "973" Youth Special Project, the National Natural Science Foundation of China, and the Outstanding Young Scientists of the Chinese Academy of Sciences.

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