Thermally Activated Delayed Fluorescent Polymer Dots for Electrochemiluminescent Sensing of Cu²⁺ Ions

A red thermally activated delayed fluorescence emitter with mitigated efficiency roll-off via a π-stacked multiple donor–acceptor structure

“…The distinctive capacity of red and near-infrared (NIR) light to penetrate the skin more deeply than other wavelengths across the light spectrum makes them appealing for a variety of applications in healthcare, bioimaging, and phototherapy. 11–13 However, conventional red/NIR TADF OLEDs exhibit notable external quantum efficiency (EQE) roll-off at luminance levels exceeding 1000 cd m −2 when compared to their blue and green counterparts, limiting their practical utility. 14–16 The significant decrease in efficiency at high luminance levels can be attributed to factors such as unbalanced charge transport, inefficient energy transfer from the host to dopant, and prolonged fluorescence lifetime of the emitters, resulting in elevated triplet exciton density and subsequent exciton quenching mechanisms including triplet-polaron quenching (TPQ), triplet–triplet annihilation (TTA), and electric-field-induced exciton dissociation.…”

Enhanced Aggregation-Induced Delayed Electrochemiluminescence Triggered by Spatial Perturbation of Organic Dots

“…More recently, aggregation-induced delayed ECL (AIDECL), integrating the virtues of TADF and aggregation induced emission (AIE) that is an enhanced luminescent phenomenon in the aggregated states, was reported, which demonstrated the capability to attain high ECL efficiency in aqueous media by constructing the D–A type compound of benzophenone (BP) as an acceptor and dimethylacridine (DMAC) as a donor, i.e., BP-DMAC . Niu et al reported polymer dots with AIDECL activity for sensitive Cu 2+ detection with a limit of detection of 0.16 nM . Despite the dramatic ECL signal enhancement, the exploration of AIDECL is still in an early stage, and most of these AIDECL emitters have still displayed relatively low ECL efficiencies, which must be further improved.…”