Canon develops world first perovskite quantum-dot inks for use in next-generation displays

Canon has announced 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 durability for the first time in the world.

Quantum dots are semiconductor nanocrystals that measure only a few nanometres in diameter and can emit light with high brightness and high colour purity. Displays with quantum-dot technology are attracting growing attention due to their wide colour gamut that makes high visual expressiveness possible. Therefore, quantum dots are sought for display  in order to achieve higher colour 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, perovskite quantum-dots are widely seen as a promising material capable of contributing to high brightness, a wider color gamut and high resolution. The wave length (color) of emitted light can be controlled by compositions and particle sizes of perovskite quantum dots.

A perovskite structure is a type of crystalline structure. 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.

Poor durability of perovskite quantum dots has thus far been a barrier to practical use.

To address the issue of durability, Canon has leveraged its proprietary technologies in the 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 recommendation while Canon's perovskite quantum-dot inks can cover 94%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 at SID Display Week 2023 in Los Angeles, USA