Micro LED is the most suitable solution for future display technology, and its full-color technology has been a recognized difficulty in the international academic community and industry in recent years. Perovskite quantum dots have high application potential in the field of Micro LED full-color display due to their many advantages in luminescence properties.
However, the shortcomings of perovskite quantum dots are also obvious, especially red-emitting perovskite quantum dots, which are less stable and less bright than green-emitting perovskite quantum dots. Therefore, exploring new quantum dot color conversion technology is of great significance and value for solving the current technical problems of Micro LED full-color display and improving my country's international competitiveness in the Micro LED display industry.
In response to the current difficulties, the Semiconductor Lighting Laboratory has proposed a brand new strategy, using red luminescent perovskite quantum dots (γ-CsPbI3) to coat green perovskite quantum dots (CsPbBr3) to form a core-shell structure that satisfies the conditions for energy transfer between the two quantum dots. γ-CsPbI3 completely absorbs the luminescence of CsPbBr3. Since CsPbBr3 transfers energy to γ-CsPbI3, γ-CsPbI3 will exhibit the excitation characteristics of CsPbBr3, which can adjust the optimal excitation wavelength of the structure.
In this work, the optimal excitation wavelength of red-emitting two-component perovskite quantum dots is gradually adjusted to the blue light region. Under blue light excitation, the photoluminescence intensity can be increased by more than 3 times, and the blue light excitation quantum yield is close to 100%, and the stability has also been significantly improved.
Figure 1 Schematic diagram of the two-component multiple coating structure perovskite quantum dot structure and non-radiative energy transfer mechanism proposed by the research team.
After adjusting the optimal excitation wavelength of the red light quantum dots to the blue light region, the researchers applied the two-component quantum dots to the blue Micro LED color conversion layer. Using the glass microhole array as a carrier, the deposited quantum dot array corresponds to the Micro LED array, achieving excellent color conversion performance, and the display color gamut can reach 135.9% of the NTSC standard.
Figure 2 Using glass microhole arrays, two-component perovskite quantum dots are applied in the color conversion layer of blue Micro LED.
This research combines the non-radiative energy transfer mechanism with Micro LED color conversion technology, using a "two-pronged approach" in terms of performance improvement and process streamlining, breaking through the current bottleneck of Micro LED red light color conversion technology, achieving high-quality Micro LED full-color display effects at a lower cost, helping to solve industrial technical problems, and promoting the industrial development of my country's Micro LED full-color display technology.
This work involves interdisciplinary fields such as physics, chemistry, microelectronics, etc. Professor Chen Zhong and Associate Professor Lin Yue from the School of Electronic Science and Technology (National Demonstration School of Microelectronics) are the co-corresponding authors, and 2020 doctoral candidates Fan Xiaotong and Assistant Professor Wang Shuli are the co-first authors. This work was funded by the National Natural Science Foundation of China (12175189, 11904302), Fujian Provincial Foreign Cooperation Project (202210004), and the Fundamental Research Funds for Central Universities (20720190005, 2072022
0085), Xiamen Major Science and Technology Project (3502Z20191015) and other projects, Xiamen University is the first completion unit of the results.
The Semiconductor Lighting and Display Laboratory of Xiamen University was established in 2006. It is one of the earliest teams in China to carry out LED application research. In the past ten years, it has won 3 first prizes and 5 second prizes in provincial and ministerial scientific research awards. The team has long been focusing on key technical issues that are stuck in the display industry and has carried out multidisciplinary research. Focusing on breaking through several major technical bottlenecks of Micro LED, the team has continued to promote core technology research on integrated circuits and achieved a series of breakthroughs.
For example: for the first time, the non-contact measurement of Micro LED DC electrical parameters was achieved, achieving a technological breakthrough in efficient detection of microchips; for the first time, composite nanostructures were used to significantly increase the red light quantum yield, breaking through the low light efficiency bottleneck of red light pixels; using semi-polar chips to achieve a 756MHz visible light communication bandwidth record in the green light band; using self-developed micro-hyperspectral equipment, the low-temperature localized luminescence mechanism of Micro LED was revealed for the first time, etc. (Source: Xiamen University)
ANNA