Evaporation materials are mainly used in the field of coatings, especially vacuum evaporating coating technology. Compared with the traditional coating technology, vacuum evaporation coating technology has the advantages of simple principle, easy equipment, less occupation of land, low cost and no pollution. In vacuum evaporation coating technology, the evaporation materials are heated in a vacuum environment. When it reaches a certain temperature, the evaporation materials will turn into a state of molecules or atoms. Because the environment is vacuum, the evaporation of materials (metal or non-metal) in this environment is much easier than normal pressure. In general, evaporation takes place rapidly in vacuum as long as the saturated vapor pressure is greater than 1.33 Pa by heating. Evaporation materials play important roles in vacuum evaporating coating technology, and it is necessary to fully understand their properties and select them appropriately.
Figure 1. A picture of vacuum evaporation coating technology device.
According to the composition, evaporation materials can be divided into the following categories:
- Metals and pure elements evaporation materials: Metals and pure elements evaporation materials include many materials such as aluminum, antimony, bismuth, chromium, gold, indium, iron, lead, magnesium, manganese and the others. Among them, aluminum is often used for coating. However, due to the chemical properties of aluminum is active and the fluidity is very good after melting, it will corrode many metals or compounds at high temperature.
- Oxides sulfides evaporation materials: Oxides sulfides evaporation materials mainly involve aluminum oxide, magnesium oxide, neodymium oxide, silicon dioxide tantalum oxide, titanium oxide, titanium oxide and the others.
- Borides selenides evaporation materials: This type of materials generally refer to molybdenum selenide, niobium selenide, tantalum selenide, tungsten selenide, zinc selenide and the others.
- The others: In addition to the materials mentioned above, the evaporation materials also include fluorides, nitrides and the others. The representatives are aluminum fluoride, calcium fluoride, boron nitride, vanadium nitride and the others.
- Elseman A M. Organometal Halide Perovskites Thin Film and Their Impact on the Efficiency of Perovskite Solar Cells[M]. Coatings and Thin-Film Technologies. 2018.