Nondestructive direct photolithography of colloidal quantum dots enabled by benzophenone-based crosslinkers
image: A benzophenone-based photosensitive crosslinker capable of achieving submicron-scale patterning under i-line photolithography without performance degradation was developed. The resulting crosslinked devices exhibited significantly enhanced electroluminescent performance compared to conventional counterparts.
Credit: Nano Research, Tsinghua University Press
Chang Gu, Ting Zhang and Chaoyu Xiang et al. have developed a novel benzophenone-based photosensitive crosslinker that overcomes critical limitations in manufacturing high-resolution quantum dot light-emitting diodes (QLEDs). This breakthrough enables direct photolithography of colloidal quantum dots (QDs) with unprecedented resolution (down to 500 nm) while preserving their optoelectronic properties—addressing a major hurdle in next-generation display commercialization.
QLEDs are poised to dominate future displays for AR/VR devices and ultra-high-definition screens due to their exceptional color purity and efficiency. However, existing patterning techniques like inkjet printing or transfer methods struggle with submicron resolution and scalability. Direct photolithography offers superior precision but traditionally degrades QDs via deep-UV damage or harmful photochemical byproducts. This study resolves these issues, enabling industrial-scale production of high-performance QLEDs.
The team designed a bifunctional crosslinker called "biBPS", featuring a byproduct-free C-H insertion mechanism that binds to QDs’ native ligands under mild i-line (365 nm) photolithography. Key advancements include: 1) Extended Absorption: Molecular engineering shifted biBPS’s photo-absorption to 365 nm, compatible with standard semiconductor fabrication tools. 2) Nondestructive Patterning: QDs retained >95% photoluminescence quantum yield after patterning, avoiding surface defects. 3) Record Resolution: The highest reported resoution for direct QD photolithography (18,000 PPI) was demonstrated with pixel sizes of ~500 nm. Due to the optimized energy-level alignment and balanced carrier mobility in the photolithographic process, performance leaps have been achieved, for example, a peak EQE of 16.48% (vs. 13.96% in pristine devices).
Zhixin Zhai, the first author, emphasized the industrial impact: "Our crosslinker eliminates the trade-off between resolution and QD integrity. For the first time, manufacturers can achieve submicron QLED pixels using existing i-line lithography infrastructure—accelerating the path to commercial AR/VR displays."
Other contributors include Wenxuan Wang, Hao Tan and Changfeng Han from Laboratory of Optoelectronic Information Technology and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, China.
This work was supported by the National Key R&D Program of China (2022YFB3606501, 2022YFB3602902), the National Natural Science Foundation of China (62404227, U23A2092), the China National Postdoctoral Program for Innovative Talents (BX20240391), the China Postdoctoral Science Foundation (2023M743623), the Key projects of National Natural Science Foundation of China (62234004), "Pioneer" and "Leading Goose" R&D Program of Zhejiang (2024C01191, 2024C01092), Ningbo Key Technologies R & D Program (2022Z085), Ningbo 3315 Programme (2020A-01-B), YONGJIANG Talent Introduction Programme (2021A-038-B, 2021A-159-G), and Ningbo Science and Technology Yongjiang 2035 Key Technology Breakthrough Plan Project (2025Z079, 2024Z146).
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Nano Research is a peer-reviewed, open access, international and interdisciplinary research journal, sponsored by Tsinghua University and the Chinese Chemical Society, published by Tsinghua University Press on the platform SciOpen. It publishes original high-quality research and significant review articles on all aspects of nanoscience and nanotechnology, ranging from basic aspects of the science of nanoscale materials to practical applications of such materials. After 18 years of development, it has become one of the most influential academic journals in the nano field. Nano Research has published more than 1,000 papers every year from 2022, with its cumulative count surpassing 7,000 articles. In 2024 InCites Journal Citation Reports, its 2024 IF is 9.0 (8.7, 5 years), and it continues to be the Q1 area among the four subject classifications. Nano Research Award, established by Nano Research together with TUP and Springer Nature in 2013, and Nano Research Young Innovators (NR45) Awards, established by Nano Research in 2018, have become international academic awards with global influence.