When a large number of microscopic material units (atoms, ions, molecules, etc.) in an inorganic structure are arranged in an orderly manner according to certain rules, the inorganics is called a crystalline inorganics. The crystalline inorganics has a fixed melting point, and the temperature remains constant during the melting process.
Due to the advantages of rich variety and simple synthesis process, crystalline inorganics has a wide range of applications in biomedicine, catalysis, and materials.
- Biomedicine: Photonic crystal material made of crystalline inorganic materials is a kind of artificially regulated structural material with periodic arrangement. The photonic band gap of photonic crystal material can regulate light in one direction or all directions, so it has a wide range of applications in the field of biomedicine. For example, medical sensors, mainly used for the early diagnosis of diseases in clinical medicine, are the key devices for preparing advanced medical equipment, and have a very important position for the development of clinical medicine. Most of today's medical sensors use complex and expensive electrochemical and enzymatic biotransmitters, of which the reaction sensitivity and accuracy have certain limitations, and "naked eye detection" cannot be achieved. The unique periodic hole structure and optical characteristics of photonic crystals provide new possibilities for naked eye detection technology of medical sensors. The photonic crystal material can be designed as a specific function sensor device to detect changes in ambient temperature, metal element content, pH value, ionic strength, blood glucose concentration, etc. It can be used clinically to diagnose diseases such as diabetes, liver and kidney disease.
Figure 1. Medical sensor made of crystalline inorganics
- Organic Chemistry: The application of crystalline inorganics in the field of organic chemistry is mainly used as a catalyst. Crystalline TiO2 is a wide-bandgap semiconductor material (Eg = 3.2eV). Being highly chemically stable, non-toxic and easy to prepare, it is one of the most widely studied semiconductor photocatalytic materials. The crystallized TiO2-based photocatalyst mainly shows in two forms, powder and thin film. The powder photocatalyst is not easy to recover, and the hydrogen and oxygen generated by photolysis water are difficult to separate, which limits its practical application. When the TiO2 photonic crystal film undergoes photolysis, due to the effect of an external electric field, the cathode and anode undergo reduction and oxidation reactions, respectively, producing hydrogen and oxygen. Therefore, crystalline TiO2 is widely used in the field of organic catalysis.
Figure 2. TiO2/SrTiO3 photonic crystal film
- Material: The boron in the main elements of the third group is an oxygen-philic element. The main forms of existence in nature are inorganic boric acid and borate. Crystallized borate compounds are widely used in industrial production and daily life due to their excellent chemical and physical properties. Crystallized rare earth borate can be used as luminescent matrix material and flame retardant material. Some crystalline alkali metal borates can be used as nonlinear optical materials and so on. Some crystalline transition metal borates have potential application prospects in the fields of conductivity and magnetism due to their unique chemical and physical properties. A solar cell is a semiconductor material that directly converts light energy into electrical energy. Crystalline silicon has a narrow band gap, high photoelectric conversion efficiency, and no pollution to the environment, so it is the most commonly used solar cell material.
Figure 3. Single crystal SiO2 solar cell
- Kunlong Zheng. (2010), "Application of a capillary crystalline material to enhance cement grout for sealing tunnel leakage." Construction and Building Materials 27, 497-505.
- WILSON S T. (1982), "Aluminophosphate molecular sieves: a new class of microporous crystalline inorganic solids." Journal of the American Chemical Society 104(4), 1146-1147.
- Zhang J. (2010), "Tailored TiO2-SrTiO3 Helerostructure Nanallube Arrays for Improved Photoelectrochemical Performance." ACS Nano 4(1), 387-395.