Red-light-excited dynamic near-infrared organic afterglow materials for in vivo bioimaging

Zhou et al. Light: Science & Applications (2026)15:271 https://doi.org/10.1038/s41377-026-02340-3 ARTICLE www.nature.com/lsa Open Access Red-light-excited dynamic near-infrared organic afterglow materials for in vivo bioimaging Lei Zhou1, Jiacheng Yang1, Zhenyi He1, Zhiqin Wu1, Ping Jiang1, Jinming Song1, Liangwei Ma1 ✉, He Tian1 and Xiang Ma 1 ✉ 1234567890():,; 1234567890():,; 1234567890():,; 1234567890():,; Abstract Extending the excitation and emission wavelengths into the red or even near-infrared region is a highly challenging yet scientifically valuable research topic in the field of organic afterglow materials. To solve this issue, we put forward a twisted intramolecular charge transfer dopant molecule design strategy, in which long-lived electron-deficient dopant is decorated with electron-rich substituent. In this way, the orbital energy level of the dopant can be lowered while maintaining the compatibility with the host. Benefiting from the twisted molecular conformation and small energy gap, the obtained dopant (CN) shows visible-light-excited afterglow with various performance (decay path, lifetime, emission wavelength) when doped into different matrices. Particularly, the maximum excitation wavelength extends to 567 nm and tails to 700 nm when CN is doped into benzophenone matrix. More importantly, the maximum emission wavelength of the afterglow extends to 725 nm (τ = 67.82 ms). We also successfully apply this material in autofluorescence-free bioimaging. This work provides a viable molecular design strategy for developing red-lightexcitable near-infrared afterglow materials and demonstrates their potential for in vivo bioimaging. Introduction Organic afterglow materials have received widespread attention due to their characteristic long emission lifetimes1–7. The prolonged emission lifetime of these materials adds a time dimension to traditional optical properties such as emission wavelength, intensity, or polarization8–11. This makes them uniquely advantageous for applications in bioimaging, advanced anti-counterfeiting, information encryption, sensing, and other fields compared to traditional fluorescent materials12–16. Although many highperformance organic afterglow materials have been successfully developed in recent years, most of the existing material systems face the issue of short excitation wavelengths (<450 nm), mainly in the ultraviolet region17–23. In contrast, visible light, especially red light, offers significant advantages in reducing phototoxicity, enhancing photostability, and improving penetration depth24–27. Correspondence: Liangwei Ma () or Xiang Ma () 1 Key Laboratory for Advanced Materials and Feringa Nobel Prize Scientist Joint Research Center, Frontiers Science Center for Materiobiology and Dynamic Chemistry, Institute of Fine Chemicals, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Meilong Road 130, Shanghai 200237, China Developing visible-light-excited organic afterglow materials is crucial for expanding their practical applications. Particularly in the field of autofluorescence-free bioimaging and biosensing, the ability to be excited by long wavelength light and emission in the near-infrared region are essential requirements. Molecules designed for visible light excitation (absorption) materials often require extending the conjugation of dyes or constructing donoracceptor (D-A) molecular systems28–32. However, the frontier molecular orbitals of such compounds are typically π-type, making it difficult to achieve sufficient spin-orbit coupling. To promote the utilization of triplet excitons, heavy atoms like bromine and iodine are often introduced into the molecular framework19,33–38. While these heavy atoms enhance the intersystem crossing (ISC) rate, they also increase the radiative transition rate of the lowest triple state (T1), thereby significantly reducing phosphorescence lifetime. The bi-component doping strategy can bypass the ISC process of the dopant molecules by utilizing interactions between the host and dopant to directly generate the triplet excited state of guest, thereby achieving long-lived afterglow39–41. Therefore, this strategy holds unique advantages in developing long-wavelength-excited © The Author(s) 2026 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. Zhou et al. Light: Science & Applications (2026)15:271 Page 2 of 10 87.25 ms lifetime. To verify our hypothesis, we grafted N, N-dimethylaniline into CK skeleton to construct a TICTtype dopant (CN, Fig. 1a). The results showed that, compound CN exhibited a clear afterglow centered at 725 nm with a 67.82 ms lifetime when doped into BPO matrix. Importantly, the maximum excitation wavelength extends to 567 nm and tails to 700 nm. Benefiting from flexibility of the molecular skeleton, the modulation of the afterglow emission decay path, lifetime, and wavelength could be achieved by changing the matrices. By adjusting the host materials, the afterglow emission wavelength could be tuned from 625 nm to 725 nm (Fig. 1b, c). We also successfully applied this material in autofluorescencefree bioimaging Fig. 1d. This work provides a viable molecular design strategy for developing red-lightexcitable near-infrared afterglow materials suitable for in vivo bioimaging. afterglow materials. However, matching the host and dopant in bi-component doping materials is often based on semi-empirical trial-and-error methods, lacking effective theoretical guidance, which greatly limits the development of novel organic afterglow materials42,43. Recently, a series of red afterglow materials based on pyrene was developed24. Notably, even after modifying with strong electron-donating structures such as methoxybenzene or N, N-dimethylaniline, the obtained derivatives still interact with the matrix to produce afterglow. These results hint that the grafting of electron-donating group does not change the compatibility with the host. This insight inspired us to utilize existing electron-deficient dopants as parent compounds and modify them with electron-rich substituents, such as N, Ndimethylaniline, to construct twisted intramolecular charge transfer ( (...truncated)