The solution deposition precursor refers to a reagent that can be used to constitute a thin film element during the solution deposition process, which should have some special properties. For example, in the usual storage process, it should have stable chemical properties, and cannot be easily volatile or decomposed. During the deposition process, the elements constituting the thin film in the solution deposition precursor need to be easily deposited on the substrate.
Solution deposition precursors can be used to prepare a wide variety of metal thin films, thus furthering application in various materials
- Electrochromic materials: Electrochromic film materials are widely used in smart windows, displays, anti-glare rearview mirrors and other products due to their low power consumption, large light adjustment range, and good memory performance. WO3 thin film is the most studied electrochromic material, and the chemical solution deposition process is often used in industry to prepare tungsten oxide thin film. However, the electrochromic properties of WO3 are largely affected by the solution deposition precursors used in the chemical solution deposition process. Using sodium tungstate as a solution deposition precursor to dissolve in deionized water to form a sodium tungstate solution, and then using chemical solution deposition method at 60℃ can prepare nanostructured WO3·2H2O thin film that has good morphology, excellent optical performance and electrochemical performance, and is the best choice for preparing photochromic materials.
- Transparent conductive film: As an important optoelectronic material, transparent conductive oxide (TCO) film has become the material basis of materials, optics, electronics, etc., and is widely used in flat panel liquid crystal displays, solar cells, surface heating elements, gas sensor and special function window materials and other fields. The n-type doped thin film of ZnO has good physical and chemical properties, and has been widely applied in the preparation of transparent conductive oxides. With zinc acetate solution and ferric nitrate solution as precursors, the Zn1-xFexO transparent conductive oxide film can be grown on the glass slide by the chemical solution deposition method. The film has a small resistivity value and a high light transmittance, a good material for preparing a transparent conductive oxide film.
- Carbon/carbon composite material: Carbon/carbon composite material combines high temperature performance of carbon material and excellent mechanical properties of composite material, and is a novel advanced composite material with excellent thermal structure-function integration. It is currently known as the most ideal high-temperature structural material under an inert atmosphere, and has been successfully used in aircraft, high-end cars, heavy vehicles, high-speed trains, racing brake discs, etc. The carbon/carbon composite material is composed of carbon fiber, pyrolytic carbon and pores. Among them, carbon fiber is generally prepared by a deposition process. Different deposition processes use different precursors. Compared with other deposition precursors, solution deposition precursors have the advantages of low cost and short cycle time in the preparation of carbon fibers. Therefore, using the solution deposition precursor is preferred for manufacturing carbon fibers. For example, using cyclohexane as a carbon source precursor can produce carbon fibers with a volumetric density of 0.5 g/cm through a chemical liquid deposition process.
Figure 1. Preparation of carbon fiber with cyclohexane as carbon source precursor
- Magnetoelectronic materials: Magnetoelectronic materials are widely used in magnetic memory, magnetic recording materials and magnetic sensitometers. Perovskite manganese oxide has become the main material of magnetoelectronic materials due to its excellent magnetoresistance effect. Therefore, it is also necessary to prepare perovskite manganese materials into perovskite manganese oxide film materials with application properties. The cost of traditional methods for preparing perovskite manganese oxide films are relatively high, most of which require high temperature, high vacuum and other strict conditions, causing certain obstacles to the industrial production of this material. The use of chemical solution deposition method avoids the above shortcomings and has become an important process for preparing perovskite thin films. Various solution deposition precursors are used in this process. The earliest precursors used to prepare perovskite manganese oxide films were metal organic compounds, such as metal alkoxide compounds, metal carboxylates, and metal diketone compounds. Now, some metal inorganic compounds are also used as precursors for preparing perovskite manganese oxide thin films, such as metal halides and metal nitrate compounds.
Figure 2. Perovskite manganese oxide film used in magnetic electronic materials
- SUN Wanchang. (2002). "Progress in rapid liquid-vaporisesd densification processing for fabrication C/C composites." Journal of the Chinese Ceramic Society 30 (4 ), 513.
- DEB S K. (1973). "Optical and photoelectric properties and colour centres in thin films of tungsten oxide." Philosophical magazine series 27(4), 801-822.
- Dey S K. (1988), "Thin-film ferroelectrics of PZT of solgel processing." Ultrasonics Ferroelectrics and Frequency Control IEEE Transactions on 35(1), 80-81.