Progress has been made in the research on the crystalline materials with photoelectric effect of ferroelectric semiconductor in Fujian Institute of Physics

Polar optoelectronic functional crystalline materials with non-centrosymmetric structures exhibit excellent optoelectronic properties such as non-linear optics, piezoelectric, pyroelectric, and ferroelectric, based on spontaneous polarization. However, only the compounds that crystallize in 10 kinds of polar point groups can produce the polarization effect. How to innovate the structural design of the polar optoelectronic functional crystal material, and achieve the uniform arrangement of the dipole moments by using the elementary elements, Polarization properties of compounds to obtain crystalline materials with excellent optoelectronic properties have become an important scientific issue in this area.

Fujian Institute of Structure Chemistry and State Key Laboratory of Chemistry and Physics, Chinese Academy of optoelectronic materials and physics researcher Luo Junhua inorganic photovoltaic functional crystal materials research team, the National Outstanding Youth Fund, the West Campus, "Team 100" Sun Zhihua researcher chaired the spring Miao Talents "project and the Outstanding Young Persons Fund of Fujian Province, the strategy of breaking induced polarization of solid phase transformation symmetry was put forward and a series of novel polar photoelectric functional crystal materials were constructed. Recently, the team based on the design strategy of breaking induction polarization induced by the symmetry of solid phase transformation obtained an example of a ferroelectric crystal material with a perovskite-like structure. During the phase transition, the cations orient along the polar axis in the same direction and produce strong polarization effect in cooperation with the metal skeleton. The study found that: under illumination, the crystal exhibits anisotropic semiconductor optoelectronic features. A significant temperature dependence of photovoltaic voltage and photovoltaic current was generated along the two-dimensional extension direction of the metal skeleton layer, and the vertical direction showed obvious photoconductivity. Further structural analysis revealed that the ferroelectric polarization effect of the material has played an important role in the photovoltaic performance The decisive role, the results of which are published in German Applied Chemistry (Angew. Chem., Int. Ed., 2016). The successful preparation of the ferroelectric semiconductor photonic crystal material will effectively expand the potential applications of inorganic / organic hybrid perovskite materials in photovoltaic solar energy and photodetection.

Previously, based on the previous exploration of the phase transition mechanism of crystal structure (Adv. Fuct. Mater., 2012, 22, 4855), the polarization effect was induced by the symmetry breaking in the solid phase transformation process. (Adv. Mater., 2013, 25, 4159, Chem. Mater., 2015, 27, 4493); and took the lead in expanding the strategy to a plastic phase change material system, obtained the ultra-high switch (Angew. Chem., Int. Ed., 2012, 51, No. 10) was obtained at the same time as the frequency-doubling switching crystal material (J. Am. Chem. Soc., 2015, 3871) and successfully applied ferroelectric crystal materials to highly sensitive pyroelectric detection (Adv. Mater., 2015, 27, 4795).

In addition, the team also previously used BO3, PO4 functional element chemistry to control the synthesis of non-centrosymmetric structure compounds, obtained a series of UV, deep UV nonlinear optical crystal materials, including the development of a series of non-layered habit of non-beryllium borate deep UV non-linear optical crystal material (J. Am. Chem. Soc., 2016, 138, 2961; J. Am. Chem. Soc., 2015, 137, 2207; Nat. Commun., 2014, 5, 4019) Phosphate deep UV nonlinear optical crystal materials (J. Am. Chem. Soc., 2014, 136, 8560; Angew. Chem., Int. Ed., 2015, 54, 4217).