The birth of quantum dot TV has triggered a color technology revolution in the industry. Quantum dot TV uses pure color quantum dot backlight technology, which can restore the image color most realistically. It is an ideal choice for virtual augmented reality technology and smart wearable display devices.
Quantum dots, also known as nanocrystals, are nanoparticles composed of II-VI or III-V elements, and their particle size is generally between 1-10nm. Different from the traditional liquid crystal display, the quantum dot display uses blue LED as the light source, which emits pure green and red light under the excitation of blue light, and then mixes the blue light to form high-quality white light. This special nanotechnology realizes the display The high color gamut coverage can highly restore the image color.
The quantum dot material systems that can be used for display are divided into the following three categories: CdSe system, InP system, and perovskite system. These three materials can be divided into cadmium-containing materials: CdSe, and cadmium-free materials: InP and perovskite. Among them, CdSe contains heavy metal Cd, which is a kind of carcinogen restricted by the EU RoHs standard.
Because CdSe itself has good stability, it is a widely used quantum dot material at present, but it is very irritating, and contact can cause nausea, headache and vomiting. Such cadmium-containing quantum dots will cause persistent pollution and damage at all stages of production, manufacturing, processing and use, and disposal.
Due to the toxicity of cadmium and its compounds, the European Union, the United States, and China have put forward corresponding regulations on the use of cadmium.
The "Administrative Measures for the Restriction of the Use of Hazardous Substances in Electrical and Electronic Products" promulgated by the Ministry of Industry and Information Technology of China in 2016 is called the Chinese version of RoHS 2.0. Among them, electrical and electronic products that include televisions in the compliance management catalog should comply with GB/T 26572-2011 on electrical and electronic products. Limit requirements for restricted substances in products. According to the "Exemption List of Restricted Substances in the Standards Compliance Management Catalog", the cadmium content requirements for quantum dot TVs are consistent with EU RoHS 2.0.
Copper indium sulfide (CIS) quantum dots are one of the most commonly used cadmium-free quantum dots and are considered good quantum dots for lighting applications due to their broad emission bands. Major quantum dot manufacturers around the world are also actively deploying cadmium-free quantum dot technology. For example, Nanosys, a cadmium-containing quantum dot giant company in the United States, proposed cadmium-free quantum dots as the main development direction at the CIDC 2020 Quantum Dot Forum, and introduced that it has developed a new Cadmium-free green quantum dot materials, etc. Cadmium-free quantum dots will be a new trend in quantum dot TVs. The development of domestic cadmium-free quantum dot materials is still slow, and there is an urgent need to speed up the development.