RESEARCH ARTICLE www.afm-journal.de Flexible Ultrahigh-Resolution Quantum-Dot Light-Emitting Diodes Lihua Lin, Zhihua Dong, Jie Wang, Hailong Hu, Weiguo Chen, Tailiang Guo, and Fushan Li* In the rapidly evolving Metaverse, enhancing user immersion through clear, lifelike, and ergonomic near-eye displays is crucial. However, existing rigid near-eye displays encounter challenges such as insufficient resolution, limited adaptability, and suboptimal visual experiences. To address these issues, a strategic shift is proposed to flexible ultrahigh-resolution (FUR) displays, which combine ultrahigh resolution with the ability to conform to individual eye curvature for a more realistic field of view. FUR quantum dot light-emitting diodes (FUR-QLEDs) featuring 9072 pixels per inch (PPI), a maximum external quantum efficiency (EQE) of 15.7%, and peak brightness of 15 163 cd m −2 are achieved through the integration of nanoimprinting and surface modification technologies. The degradation mechanism of FUR-QLEDs under bending fatigue tests is investigated, identifying the high elastic modulus of the insulating patterned film as the primary cause through theoretical analysis, simulation, and experimental characterizations. Optimizing the elastic modulus of the patterned film enabled to maintain 91% of its initial brightness after 400 bending cycles, demonstrating exceptional bending stability and durability of FUR-QLEDs. 1. Introduction Quantum dot light-emitting diodes (QLEDs) are innovative semi- conductor electroluminescent devices distinguished by their ad- justable emission wavelength, high color saturation, and robust stability. [ 1–11 ] They have versatile applications in next-generation wide color gamut, high contrast, and flexible displays, as sub- stantiated by numerous studies. [ 7,12–16 ] Currently, QLED de- vices made on traditional rigid substrates have achieved signif- icant advancements in external quantum efficiency (EQE) and device stability. Specifically, the EQE of QLEDs, covering the fundamental colors of red, [ 17,18] green, [ 19,20 ] and blue, [ 21] has L. Lin, Z. Dong, J. Wang, H. Hu, W. Chen, T. Guo, F. Li Institute of Optoelectronic Technology Fuzhou University Fuzhou 350116, P. R. China E-mail: fsli@fzu.edu.cn L. Lin, H. Hu, T. Guo, F. Li Fujian Science and Technology Innovation Laboratory for Optoelectronic Information of China Fuzhou 350108, P. R. China The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adfm.202408604 DOI: 10.1002/adfm.202408604 surpassed 20%. Additionally, the op- erational lifetime of these devices is approaching or reaching the necessary criteria for practical applications. [ 21,22 ] With the rapid advancement of information technologies, including artificial intelli- gence and wearable devices, the demand for near-eye display devices has steadily increased. [ 23–26 ] This demand includes high resolution, flexibility, light weight, and other features. Particularly within the rapidly evolving Metaverse, built on cutting-edge technologies such as virtual reality (VR), augmented reality (AR), and artificial intelligence (AI), the prerequisites for accessing the Metaverse now include research and development focusing on ultrahigh resolution (reaching 10 000 pixels per inch (PPI)), adaptability to in- dividual fields of view, and lightweight, portable near-eye display devices. [ 27 ] Despite progress in near-eye display de- vice technology, several challenges and de- fects remain. Insufficient resolution and pixel density cause blurred images and a noticeable “screen door effect,” undermining the overall visual experience. Additionally, AR and VR technologies typically use rigid displays that cannot adjust for differences in pupil position, distance, eye movement, or sight height, which are essential for optimizing the field of view for different users. This limitation can result in visual dis- comfort, such as eye fatigue, headaches, and dizziness. Moreover, rigid screens cannot provide a wide and natural field of view, caus- ing users to perceive the edges of virtual images as obvious or truncated, thus hindering a personalized and comfortable virtual experience. Furthermore, the adoption of lightweight near-eye devices significantly enhances user comfort, which is not pos- sible with rigid screens. Given the significant limitations and challenges in current near-eye display devices, such as inadequate resolution, inabil- ity to adapt to individual user differences, and suboptimal visual experiences, we propose developing flexible ultrahigh-resolution quantum dot light-emitting diodes (FUR-QLEDs) to address these issues. The flexible design allows adjustment to the cur- vature of the eyeball, creating a display interface that aligns more seamlessly with the anatomical contours of the human eye. This adjustment mitigates the visibility of edges, enhances overall comfort, and provides a more natural viewing experience. Addi- tionally, it can conform to the shape of the head and the position Adv. Funct. Mater. 2024, 34, 2408604 © 2024 Wiley-VCH GmbH 2408604 (1 of 12)