TOKYO, May 29, 2023—Canon Inc. announced today that the company has developed a quantum-dot ink with a perovskite structure (perovskite quantum-dot ink) as a material for next-generation quantum-dot displays, and has successfully demonstrated its practical durability1 for the first time2 in the world.
Perovskite quantum-dot inks developed by Canon emitting light
The performance and image quality of display devices continue to rapidly improve, and towards this end, one such approach that is gaining momentum is applying quantum-dot technologies (QD) to meet the need for displays with higher image quality.
Quantum dots are semiconductor nanocrystals that measure only a few nanometers in diameter and can emit light with high brightness and high color purity. Displays with quantum-dot technology are attracting growing attention due to their wide color gamut that makes possible high visual expressiveness. Therefore, quantum dots for display is sought to achieve higher color purity and higher light utilization efficiency. In addition, though cadmium (Cd) has thus far been the preferred material for quantum dots, due to environmental concerns, there is a growing interest in Cd-free materials.
With these requirements in mind, Canon has focused on the development of perovskite quantum-dot inks. Perovskite quantum dots are considered an effective Cd-free approach other than InP (indium phosphide) quantum dots. In terms of color purity and light efficiency, many see perovskite quantum-dots as a promising material capable of contributing to high brightness, a wide color gamut and high resolution. However, poor durability has thus far been a barrier to practical use.
To address the issue of durability, Canon is leveraging its proprietary technologies nurtured through development of ink and toner for printers. The company has established a unique method to form a protective shell on quantum dots, thereby achieving practically durable perovskite-dot ink with retained color purity and light usage efficiency.
InP quantum-dot ink covers 88% of the color gamut based on the ITU-R BT. 2020 recommendation3, while Canon's perovskite quantum-dot inks can cover 94%4 of the gamut. In addition, the high efficiency of light use is expected to reduce power consumption of quantum dots by approximately 20%5 compared to conventional technology.
Canon's quantum-dot inks have the potential to help realize next-generation OLED displays with ultra-high definition, such as quantum-dot 8K displays, a technology that thus far has been unachievable.
The results of technological development of the ink and the technology for mass-production of high-quality perovskite quantum dots were announced on May 26, 2023 (local time) at SID Display Week 2023 in Los Angeles, USA.
Color gamut of the newly developed perovskite quantum-dot inks
High resolution print samples of the perovskite quantum-dot inks
Conceptual diagram of an OLED display utilizing quantum-dot technology
Perovskite quantum dots can express a wide range of colors
A perovskite structure is one type of crystalline structures. By changing the elements that compose a perovskite structure, a variety of properties can be manifested, including superconductivity, ferroelectricity, fluorescence and photoelectric conversion. Due to this versatility, a perovskite structure holds great potential for use as functional materials. In recent years, perovskite solar cells have attracted attention thanks to their low cost and versatility that enables them to be used anywhere.