In the study of material luminescence, dispersed molecules are usually ideal research objects, while aggregated states are often chaotic states that are unavoidable. For example, when molecules change from a dispersed state to an aggregated state, Beer-Lambert's law describing the light absorption process is no longer applicable; when molecular aggregates are formed, the fluorescence decreases or disappears, which manifests as aggregation-caused quenching (Aggregation-caused quenching, ACQ). Interestingly, some alternative molecules exhibit aggregation-induced emission (AIE), that is, their single molecules emit light weakly or not at all, but they exhibit enhanced luminescence after aggregation. After two decades of development, the research of aggregation-induced luminescence has focused on the molecular "more and more the brighter" and the new structure, new properties and new functions of the luminous body endowed by the molecular collective, which has promoted the research in the field of luminescence and the development of aggregation science. At this stage, aggregate state luminescence has penetrated into the fields of molecular and excited state electronic control, mesoscopic aggregate state structure, macroscopic material properties and device performance, and has shown great application potential.
In the context of this development, in order to summarize the latest progress in aggregated luminescence research, promote academic exchanges in related disciplines, and cross-fusion of related fields, we organized the writing of the topic "aggregated luminescence", focusing on small organic molecules and metals- The applications of aggregated luminescent materials such as organic complexes and metal nanoclusters in the fields of luminescence, sensing, and biomedicine are reviewed on cutting-edge research reports and research progress. In the research of small molecule luminescence, Li Zhen found that molecular stacking is the key factor that affects the force response of solid organic small molecules to the luminescence behavior; Zhu Liangliang proposed a new mechanism for enhancing the luminescence of hexathiopyridine in the organic phase; Zeng Zebing summarized organic free radicals The open-shell molecular structure characteristics, structure-activity relationship, excited state luminescence mechanism, free radical luminescence prospects and cutting-edge original research challenges of the luminous body. In terms of sensor detection, Ren Xiangkui reported on the pH response performance of aggregation-induced luminescence small molecules; Li Kai and Zang Shuangquan developed the design and synthesis of complex aggregation-induced luminescence molecules and their detection methods for Hg2+; Zhu Weihong and Wang Qi summarized In recent years, the application progress of aggregation-induced luminescent materials in the detection of pesticide residues, veterinary drug residues, heavy metals, pathogens, food additives and other food safety testing. In the field of biomedicine, Hongmin Chen and Wenjing Sun introduced the applications of gold, silver, and copper AIE metal nanoclusters in analytical sensing and biomedical fields, and discussed the AIE characteristics and applications of other iridium complexes. Chen Ming and Qin Anjun summarized the design method, imaging mechanism of mitochondrial-targeted AIE probes, and the research direction of differentiating cancer cells and normal cells, circulating tumor cells and white blood cells; Wang Dong's photodynamics guided by fluorescence imaging The three aspects of treatment, photoacoustic imaging-guided photothermal therapy and multimodal imaging-guided collaborative therapy summarize the latest research progress of aggregation-induced luminescent materials in the field of optical diagnosis and treatment. The above academic achievements show the new mechanism of luminescence of aggregated luminescent molecules, as well as the new progress of aggregated luminescent materials in the fields of sensing and biomedicine. I hope that the dissemination of academic ideas can trigger the inspiration of readers and friends, and promote the development of related disciplines together. .
Thank you colleagues for your outstanding contributions in the field of luminescence, and look forward to your joint efforts to enable our original research to better go to the world and contribute more Chinese wisdom and power to the development of related fields! Finally, I hope that this special issue will showcase the latest research results in the field of aggregation-induced luminescence and aggregation science in my country, strive to enhance the influence of the Journal of Luminescence in the field of optics, and actively promote the sharing of scientific and technological achievements and academic exchanges in this field.