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Updated: Feb 5, 2026

Production and Characterization of Vacuum Deposited Organic Light Emitting Diodes
Published on: November 16, 2018
Light-Emitting Covalent Organic Frameworks: Fluorescence Improving via Pinpoint Surgery and Selective Switch-On
Zhongping Li1,2, Ning Huang1, Ka Hung Lee3,4
1Department of Chemistry, Faculty of Science , National University of Singapore , 3 Science Drive 3, Singapore 117543 , Singapore.
Abstract:
Covalent organic frameworks (COFs) offer ordered π structures that are useful for developing light-emitting materials. However, most COFs are weak in luminescence. Here we report the conversion of less emissive COFs into light-emitting materials via a pinpoint surgery on the pore walls. Deprotonation of the N-H bond to form an anionic nitrogen species in the hydrazone linkage can eliminate the nitrogen-related fluorescence quenching pathway. The resulting COF enhances the fluorescence in a linear proportion to the progress of deprotonation, achieving a 3.8-fold improved emission. This pinpoint N-H cleavage on the pore walls can be driven only by the fluoride anion while other halogen anions, including chloride, bromide, and iodide, remain inactive, enabling the selective fluorescence switch-on sensing of the fluoride anion at a ppb level.
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