Synergism of Photo-Induced Electron Transfer and Aggregation-Induced Quenching Mechanisms for Highly Sensitive Detection of Silver Ion and Captopril

Carbon-based nanoprobes, with excellent physicochemical performance and biocompatibility, are a kind of ideal nanomaterial for biosensing. Herein, we designed and prepared novel oxygen-doped nitrogen-enrichment carbon nanoribbons (ONCNs) with an excellent optical performance and uniform morphology, which could be used as a dual-mode fluorescence probe for the detection of Ag⁺ ion and captopril (Ctl) based on the synergism of photo-induced electron transfer and aggregation-induced quenching mechanisms. By recording the changes in fluorescent intensities of ONCNs, the Ag⁺ ion and Ctl concentrations can be easily tested in real samples. The results displayed that two good linear relationships existed between the change in fluorescent intensity of ONCNs and the concentrations of Ag⁺ ion and Ctl in the ranges of 3 μM to 30 μM and 1 μM to 30 μM, with the detection limit of 0.78 µM and 74 nM, respectively. The proposed sensing platform has also been successfully applied for the Ctl analysis in commercial tablet samples based on its high selectivity, proving its value in practical applications.

Through-Space Interactions Enable Aggregation-Induced Quenching Suppression and Spin-Flipping Enhancement of Carbonyl-Nitrogen-Based Multiple Resonance Thermally Activated Delayed Fluorescence Emitters

Multiple resonance (MR) thermally activated delayed fluorescence (TADF) materials hold significant potential for applications in high color purity and highly efficient organic light-emitting diodes (OLEDs). However, their inherently large planar structures often result in severe aggregation-induced quenching and slow spin-flip processes, presenting significant challenges that limit their practical applications. In this study, we designed and synthesized two MR-TADF molecules, tCON-Cz and tCON-2tBuCz, by incorporating a tCON backbone with carbazole or 3,6-di-tert-butylcarbazole at the ortho position of the phenyl ring. This strategic design introduces a highly twisted three-dimensional structure, effectively mitigating aggregation-induced quenching. Additionally, it creates a through-space charge transfer channel that facilitates reverse intersystem crossing, thereby enhancing TADF efficiency. As a result, both molecules exhibit high photoluminescence quantum yields. When incorporated into devices, these OLEDs demonstrated remarkable performance, achieving high external quantum efficiencies of 23.70% for tCON-Cz and 22.84% for tCON-2tBuCz at doping concentrations as high as 20%. Notably, both devices retained the narrow full width at half-maximum of around 36 nm, consistent with the parent tCON skeleton, ensuring superior color purity.