Air is the foundation of human survival. We can choose water and food, but we cannot choose the surrounding air. As we breathe air, harmful substances also enter the human body, posing a threat to our health. Especially the pollutants in indoor air will continue to stack and ferment indoors, and over time, it may even become a "toxic gas chamber". According to a survey by the World Health Organization, the number of deaths caused by indoor pollution worldwide each year has reached 4 million, while the number of deaths caused by indoor pollution in China each year is as high as 111000.

Classification of Air Purification and Principle of UVA Photocatalytic Purification

The air cannot be selected, but it can be improved. Therefore, air purifiers have emerged as the most direct way to effectively remove toxic gases such as formaldehyde and TVOC, sterilize, and purify indoor air. According to the working principle of purification, air purifiers are generally divided into three categories: passive (filter purification type), active (non filter type), and dual (active purification+passive purification).

The working principle of passive purification is to use a fan to draw air into the machine, filter the air through the built-in filter, and mainly filter dust, odors, toxic gases, and kill some bacteria. The filter is further divided into: dust collection filter, formaldehyde removal filter, deodorization filter, HEPA filter, etc. The cost of HEPA filter is relatively high, which can decompose toxic gases and sterilize, especially to suppress secondary pollution. The effectiveness of such products depends on the power of the fan and the quality of the filter screen, but the drawbacks are also obvious. For example, the filter screen is a consumable that needs to be replaced regularly and is prone to producing purification dead corners.

The working principle of active purification is to effectively and actively release purification and sterilization factors into the air, utilizing the characteristic of air diffusion to reach various corners of the room for blind spot purification of the air. According to the principle of active sterilization, the technology of such products has evolved from the first generation of silver negative ions to new generation technologies such as negative ions, plasma, ozone, photocatalysts, etc.

Among them, photocatalyst is a general term for a type of semiconductor material with photocatalytic function, represented by nanoscale titanium dioxide. It is coated on the surface of the substrate, and under the action of ultraviolet light, it produces strong catalytic degradation function: it can effectively degrade toxic and harmful gases in the air; It can effectively kill various bacteria and decompose and harmless treat the toxins released by bacteria or fungi; At the same time, it also has functions such as formaldehyde removal, deodorization, anti pollution, and air purification.

The catalytic effect of photocatalysts depends on two factors: UV light source and reaction area. In terms of UV light sources, UV light below 387nm wavelength can stimulate the catalytic effect of photocatalysts, thereby generating more hydroxyl radicals and reactive oxygen species, achieving bactericidal effects by oxidizing bacteria and viruses.

At present, the global epidemic situation of novel coronavirus pneumonia is relatively severe, and UV disinfection related products are also concerned. Although UVA photocatalyst technology cannot directly kill novel coronavirus, it belongs to the indirect bactericidal effect of ultraviolet light, and the free radicals generated by it can sterilize bacteria such as Escherichia coli, Staphylococcus albus and viruses (such as influenza virus), and almost all the free radicals generated by microorganisms through UVA photocatalyst can be oxidized and decomposed.

LatticePower believes that compared to the sterilization and disinfection ability of UVC, UVA photocatalyst sterilization and disinfection require a longer time. However, UVC ultraviolet rays need to reach a certain dosage to quickly kill bacteria, which can also cause harm to the human body. Therefore, currently, indoor UVC ultraviolet sterilization is mostly carried out under unmanned conditions. In addition, UVC LEDs are limited by factors such as conversion efficiency, low power, and high material costs, and have not yet been widely used in large indoor spaces. However, they can also effectively shield against the risk of harm to human health. So, UVA photocatalyst air purification equipped with UVC LED can achieve complementary sterilization and can be used in human environments, which is a suitable solution. In addition to UVC LEDs that have direct bactericidal effects, this epidemic has also stimulated and promoted the development of UVA photocatalyst products.

Patent PCO air purification technology: perfect combination of silicon substrate UVA LED technology and photocatalyst

After the outbreak of the epidemic, manufacturers such as Riya are also accelerating the development of UVA LED photocatalytic air purification products.LatticePower has also advanced the development schedule of UV LED products, concentrated advantageous resources, and focused on product development in two directions: air purification and sterilization and disinfection. LatticePower UVA LED photocatalyst car air purifiers and UVC LED surface sterilization boxes are expected to be widely launched in the market in early April.

LatticePower has been researching patented silicon substrate UVA LED technology and photocatalyst air purification modules for use in refrigerators for a long time, and has developed a patented PCO air purification technology based on this. Research on Crystal Energy Optoelectronics has found that under the excitation of 365nm-375nm UVA LED light source, photocatalyst TiO2 nanoparticles can generate highly reactive hydroxyl radicals and superoxide anion radicals. These ions react with organic compounds to generate carbon dioxide and water, which have extremely strong functions of sterilization, deodorization, mold prevention, self-cleaning, and air purification.

It is worth noting that for the two key factors of UV light source and reaction area, crystal energy optoelectronics has achieved breakthroughs.

In terms of UV light sources, the 365-375nm band chip developed by Crystal Energy Optoelectronics has achieved more than 98% of the excited light below 387nm, greatly improving the utilization efficiency of the light source. Crystal Energy Optoelectronics indicates that in order to quickly excite photocatalysts, UV energy needs to reach a certain value. Due to the uneven distribution of light energy emitted by LEDs, the area of photocatalysts that can be excited by a single LED is very small. If a 365nm mercury lamp is used, due to the small proportion of light below 387nm and severe light attenuation, it requires high power and cannot be used in many environments. LatticePower has obtained the optimal UV energy and UV light distribution of the excitation luminescent catalyst through a large number of experiments. Using its own packaging technology, several corresponding UV lamp beads have been developed, improving the uniformity of light distribution, increasing the area of the excitation luminescent catalyst, and reducing the use of lamp beads.

In terms of reaction area, the particle size of photocatalysts is only 5-10nm, making it extremely difficult to combine with other substances. Therefore, many manufacturers use the method of adding binders to attach photocatalysts to the carrier. However, the photocatalyst particles will be covered by the binder, resulting in only a portion of the exposed photocatalyst particles on the surface. The reaction area is small and the effect is poor, which leads to customers not recognizing the photocatalyst product. In this regard, Crystal Energy Optoelectronics adopts a carrier with good adhesion to photocatalyst particles, and through a special adhesion process, generates a layer of photocatalyst film, which allows the photocatalyst to uniformly and densely adhere to the carrier and be exposed on the surface, greatly increasing the reaction area of the photocatalyst, truly achieving module miniaturization. Moreover, photocatalysts can adhere to the carrier for a long time without falling off.

Based on the breakthroughs in the above two aspects, LatticePower has continuously tested various conditions (temperature, humidity, wind speed, power, etc.) for three years, combined with a unique catalyst adhesion process, and developed a patented PCO air purification technology. The independently developed high-efficiency silicon substrate UVA LED light source is perfectly combined with photocatalysts, which can simultaneously kill bacteria, remove harmful gases, remove dust, and fresh air. It can be applied to dust In complex environments such as water vapor and vibration. At present, related products have entered the fields of air purifiers, refrigerators, pet crates, sterilization boxes, automobiles, industrial waste gases, etc.

LatticePower believes that compared with traditional air purification systems, UVA LED photocatalyst air purification systems have unparalleled bactericidal effects compared to traditional inorganic antibacterial agents through photocatalytic sterilization. They have advantages such as persistence, broad-spectrum, heat resistance, no drug resistance, and thorough sterilization. At the same time, they also have advantages such as non-toxic, odorless, pollution-free, high efficiency, and long service life. Compared to other purification technologies, LatticePower believes that photocatalysts have the highest comprehensive cost-effectiveness.

The application of sterilization and disinfection requires the joint promotion of the industrial chain, and UVA photocatalyst purification products gain business opportunities

UV LED is a key development area for Crystal Energy Optoelectronics, and the outbreak of the epidemic has accelerated its pace of launching UV LED products. Next, LatticePower will develop a series of home and public air purification products based on PCO technology, as well as sterilization and disinfection products based on UVC LED applications.

LatticePower believes that the application of UV LEDs is still in an exploratory stage, and the application of sterilization and disinfection still requires collaborative progress in technology, application, standards, and other aspects from the industry chain level to provide consumers with truly qualified and effective products.

Regarding the market recognition and future development potential of UVA photocatalytic air purification systems, LatticePower points out that the concept of photocatalysts has been hyped up in the past few years, and true photocatalyst products have higher costs and can only be judged based on testing reports. Therefore, what consumers buy may not be true photocatalyst purification products. In view of this, the entire market lacks confidence in photocatalytic products.

However, LatticePower believes that after the outbreak of this epidemic, consumers will also have a more rational view of photocatalytic purification products, and their efficient mechanism of action will be recognized by more and more consumers. The next one or two years will be an explosive year for UVA LED air purification.

According to LEDinside analysis, the sterilization and purification market will be the main driving force for the growth of the UV LED market in the next 5 years, among which the UVA LED photocatalyst air purification market will maintain stable growth in the future. The current epidemic has greatly stimulated the market demand for UV series sterilization and disinfection products, and undoubtedly accelerated the development of UVA LED photocatalyst purification products.

(Source: LEDinside)