1.Overview
Polysilazane is a highly reactive polymer with Si-N bond as the main chain, which is capable of reacting strongly with water, oxygen and many polar substances. This material has a wide range of applications in fields such as ceramics, aviation, aerospace and the coatings industry. According to its structure, polysilazane can be divided into two categories: organic and inorganic. Organic polysilazanes have organic groups in their side chains, whereas inorganic polysilazanes, also known as fully hydrogenated polysilazanes or PHPS, have a molecule that contains only three elements: silicon, nitrogen, and hydrogen.PHPS are mainly used in the production of precursors for ceramics and insulation materials due to their simple structure and high market value.PHPS do not contain organic groups and can therefore be converted in a variety of ways at lower temperatures, and they have good adhesion to substrates. adhesion to the substrate. The characteristics of the transformed coatings include corrosion resistance, high and low temperature resistance, gas barrier, long term durability, transparency, and scratch resistance, and are therefore widely used in the preparation of coatings. In optoelectronics technology, an important branch of modern science, the development of coating technology is a challenge, and PHPS coating technology plays a crucial role in improving the performance of optoelectronic devices and solving the key technological challenges in the field of optoelectronics.
2. Application of PHPS Coatings
2.1 As dielectric layer
Silica dielectric layers prepared by the liquid phase method of PHPS are popular because they can address the shortcomings of traditional methods such as thermal oxidation, chemical vapor deposition (CVD) and plasma-enhanced chemical vapor deposition (PECVD), etc. The molecular structure of PHPS has a significant impact on the performance of the dielectric layers it prepares. In one study, coating compositions were prepared using PHPS with molecular masses in the range of 800 to 2,500 and 3,000 to 8,000, and with weight-average molecular weight to number-average molecular weight ratios between 6 and 12. The compositions were coated on interstitial substrates and heated at temperatures below 1000°C to form a siliceous film deep into the interstices. In addition to focusing on molecular mass, more research has focused on the effect of the content of specific elements or groups in PHPS on coating properties.
2.2 As a barrier layer
Barrier layers, especially those that act as a barrier to gases such as water vapor, are a common type of coating on the surfaces of electronic and optical devices. In one study, a barrier layer was developed using PHPS, and this barrier layer, together with an adhesive layer, formed an adhesive sheet. The barrier layer had a surface density ranging from 2.4 to 4.0 g-cm-³, with 60% to 75%, 0% to 10%, and 25% to 35% oxygen, nitrogen, and silicon, respectively, which was one of the early patents for the development of barrier layers using PHPS. Another study investigated the effect of PHPS structure on gas barrier properties and found that by adjusting the ratio of SiH3 to SiH and SiH2 to 1:(10 to 30), a gas barrier film with excellent stability under high temperature and high humidity conditions could be produced.
2.3 As optical film
PHPS is commonly used in the manufacture of optical films by combining with modified raw materials to form a composite material that can be used in the preparation of optical films. A method of preparing a low refractive index membrane using a combination of PHPS and at least one organic polymer selected from silicone-containing silazanes, silicone-oxy-silazanes, and urethane-containing silicone-containing silicone-containing silicone-containing silicone-containing silicone. The PHPS-containing solution was mixed with the fluoropolymer-containing solution and coated to produce a high-strength, oleic acid-resistant and easy-sliding silica optical film layer A spiropyran (SP)-doped silica coating was prepared using a xylene solution of PHPS as a precursor; the film changed from a transparent light yellow color to a red color with an increase in absorbance at 500 nm as the PHPS was converted to silica. After exposure treatment, the films deepened in color and exhibited reversible photochromic properties, demonstrating their potential for optical film applications.
2.4 Other applications
The use of PHPS in solar cell coatings has increased significantly in recent years, and it plays a variety of key roles in solar cell devices. For example, PHPS is used to make solar cell dielectric barrier layers that are placed between a metal or glass substrate and a CIS (copper indium sulfide) or CIGSe (copper indium gallium selenide) photovoltaic structure. Thin-film solar cell encapsulation layers made with PHPS, which allow chalcopyrite-based solar cells to have an average reflectance of less than 95% in the 300 to 900 nm light band and more than 200% in the 1100 to 1500 nm band, showing excellent resistance to aging.PHPS is used to prepare anti-glare films for solar cells, which are equipped with an appropriate anti-glare surface texture and can effectively remove surface contamination. Vacuum UV light was used to convert PHPS into silica to encapsulate flexible chalcogenide solar cells (PSCs), and in order to prevent the degradation of PSCs caused by the PHPS solution and VUV (λ = 172 nm) light, CdSe/ZnS quantum dots were used as a barrier layer distributed on a polydimethylsiloxane substrate, and the realized encapsulation layer had a very low water vapor permeability, which made the flexible solar cell's The room temperature service life of the flexible solar cell was increased by more than 400 hours.
In addition, by dissolving PHPS in xylene and hydrolyzing it with ammonia, the chalcogenide film was further adhered to the dense layer of titanium oxide, which provides a new idea for the mass production of chalcogenide photovoltaics.

Room termperature curing polysilazane, pls check IOTA 9150, IOTA 9150A. 
High termperature curing polysilazane, pls check IOTA 9108, IOTA 9118.