Thermally Activated Delayed Fluorescent Polymer Dots for Electrochemiluminescent Sensing of Cu<sup>2+</sup> Ions
Xingzi Zou, Zihui Zeng, Bolin Zhao, Yifei Yue, Zhenwei Xu, Yuwei Zhang, Yingying Fu, Zhiyuan Xie, Li Niu, Baohua Zhang
Abstract
Thermally activated delayed fluorescent (TADF)-based electrochemiluminescence (ECL) (TADF-ECL) has attracted attention owing to its potential to achieve the ideal 100% charge-to-photon conversion capability (100% Φ ECL ), which is important to boost ECL biosensing and imaging applications. However, achieving efficient aqueous TADF-ECL using TADF-based polymer dots (TADF-Pdots) is challenging. It is not clear if the unique TADF photophysical properties of TADF-Pdots play a role in ECL emission and how they differ from those of traditional fluorescent-Pdots. In this study, conjugated TADF-Pdots and FL-Pdots were prepared for the first time to systematically confirm the unique characteristics and superiorities of TADF-Pdots to achieve highly efficient aqueous ECL. The ECL spectra of these prototype ECL systems were nearly identical to the intrinsic PL spectra of the Pdots, which were unambiguously confirmed to exhibit photophysical TADF or FL. Meanwhile, the first efficient metal–ion sensing system [e.g., Cu 2+, with a limit of detection of 0.16 nM (signal/noise = 3)] using aqueous TADF-ECL is reported.