Quantum dots are tiny semiconductor nano materials with color-tunable and high-efficiency photoluminescence, which have been successfully applied in different display technology such as liquid crystal displays (LCDs), organic light-emitting diodes (OLEDs), and micro light-emitting diodes (Micro-LEDs). In 2023, the Nobel Prize in Chemistry rewards the discovery and development of quantum dots. Perovskite quantum dots (PQDs) are emerging display materials with high absorption coefficient, low cost and easy processability, and less environmental impact. In 2015, Prof. Zhong and his co-workers demonstrated the in-situ fabrication of PQDs in polymeric matrix. In 2016, Zhijing Technology (Beijing) Co., Ltd. was founded to promote the scale-up fabrication and display applications of PQDs. After years efforts, they developed different in-situ fabrication techniques toward scale-up fabrications, including such as in-situ blade coating, in-situ spray drying, in-situ extrusion, in-situ inkjet printing, and in-situ lithography, etc. Recently, they solved the stability issues of PQDs and achieved their successful use in Skyworth's TV products. Instead of 630 nm in the regular quantum-dot light-emitting diode (QLED) TV products, they firstly introduced the 650 nm deep-red emissive PQDs to enhanced the eye care capability of TV products.
Very recently, the progress in spray-drying fabrication of PQDs is published as a research article in the journal Engineering in January 2025, titled "Spray-Drying Fabrication of Perovskite Quantum-Dot-Embedded Polymer Microspheres for Display Applications." They show the scale-up fabrication of 2000 kg per year. They also explored the use of PQDs in the backlights of LCD display panels. The PQD-based optical films exhibit excellent wet, thermal, and blue light irradiation stability. The brightness decays for 1000 hours are within 10% for the aging tests at 60 °C with 90% relative humidity and 70 °C with 150 W/m2 455 nm blue light irradiation.
The researchers also demonstrated the use of PQD-embedded polymer microspheres as color converters in full-color Micro-LED display applications with a minimum pixel size of 10 μm. The reported spray-drying fabrication method provides a low-cost approach for the scale-up production of PQDs. The as-fabricated PQD-embedded polymer microspheres exhibit long-term operational stability, making them highly competitive as color converters for display technology.
