Rongrong Xu, Qianxi Yin, Junyi You, Xiaoting Wang, Mulin Li, Xianliang Huang, Jun Chen, Haibo Zeng
First published: 12 February 2025
https://doi.org/10.1002/adom.202403132
Abstract
Laser patterning of perovskite is a novel technology with the advantages of high speed, programmability, and maskless, which is ideal for fabricating micro light-emitting diodes (micro-LED) color conversion layers (CCL). This work reports a method for laser in situ synthesis of wide bandgap tunable perovskite with an emission spectrum from 475 to 667 nm. Based on the photonic effect of continuous wave (CW) laser and the thermal quenching phenomenon of perovskite, ultra-high precision patterning with a minimum linewidth of 750 nm and a maximum dot-pixel per inch (PPI) of 5684 is achieved. More importantly, significant improvements in perovskite stability and integration of red-green dual-color dot arrays are achieved through in-depth studies of polymer matrices and precursor solvents. The red-green dual-color integrated dot arrays using blue micro-LED chips, which is a great impetus to the research of micro-LED full-color displays, are also successfully excited.
Introduction
With the continuous growth of scientific research and demand in the display market, micro-light-emitting diodes (micro-LED) have emerged as a next-generation display technology. In recent years, micro-LED has made significant progress in the display market due to its excellent performance in color, resolution, lifespan, and energy consumption. However, research on micro-LED is still in its early stages and faces numerous challenges, with achieving high-precision full-color displays being one of the key research topics.
Currently, the mainstream technologies for full-color micro-LED displays are the RGB three-color LED method and the UV/blue LED with phosphor method. While the RGB three-color LED method is commonly used by mainstream manufacturers, it has gradually exposed some drawbacks as the resolution and display size increase, such as limited transmission efficiency, high cost, and lower reproducibility. The phosphor-based UV/blue LED method, on the other hand, offers advantages such as higher color purity and saturation, along with a simpler structure, making it a promising method for realizing full-color micro-LED displays in the future.
The key challenge of the UV/blue LED phosphor method lies in the preparation of high-resolution color conversion layers (CCLs). Perovskite, due to its high color purity, tunable emission color, and high fluorescence quantum yield, has attracted widespread attention in the display industry. Laser-driven perovskite imaging has emerged as a new technology in the field of CCLs. Compared to patterning methods like inkjet printing, photolithography, and nanoimprint lithography, laser processing offers advantages such as fast processing speed, high reliability, high precision, maskless operation, and relatively clean processing. These characteristics make it highly suitable for fabricating high-resolution CCLs.
In recent years, many researchers have extensively studied laser in situ synthesis and imaging of perovskite. Zhan et al. reported a method combining in situ manufacturing and direct laser writing based on a 405 nm nanosecond laser. By adjusting key parameters in the laser writing process, a minimum line width of 900 nm was achieved. Nie et al. also proposed a continuous wave (CW) laser imaging method that can directly induce crystallization of perovskite nanoparticles in a polyvinylidene fluoride (PVDF) matrix. However, the inherent instability of perovskite lattices leads to structural degradation, and integration of small-size red-green dual-color dot arrays is currently not feasible. These challenges hinder the application of this technology in micro-LEDs.
Researchers from Nanjing University of Science and Technology, including Hai-Bo Zeng and Jun Chen, reported a method for laser in situ synthesis of wide bandgap tunable perovskite with an emission spectrum from 475 to 667 nm. Through the photonics effects of CW lasers and the thermal quenching phenomenon of perovskite, ultra-high precision patterning with a minimum linewidth of 750 nm and a maximum dot-pixel per inch (PPI) of 5684 was achieved. More importantly, through in-depth research on polymer matrices and precursor solvents, significant improvements in perovskite stability and integration of red-green dual-color dot arrays were achieved. The red-green dual-color integrated dot arrays using blue micro-LED chips were also successfully excited, providing a significant boost to the research of micro-LED full-color displays.
Conclusion
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