A triphenylacrylonitrile phenanthroimidazole cored butterfly shaped AIE chromophore for blue and HLCT sensitized fluorescent OLEDs

Abstract

We have synthesized butterfly shaped emitters, TPATPA-PPI and TPATPA-CNPPI having hybridized local and charge-transfer (HLCT) emissive state with hot exciton channel to harvest high-lying triplet excitons (Tn) through reverse intersystem...

Recent progress in imidazole based efficient near ultraviolet/blue hybridized local charge transfer (HLCT) characteristic fluorophores for organic light-emitting diodes

“…23). 150 The PLQYs of TPATPA-PPI 110 (50.0%) and TPATPA-CNPPI 111 (61.0%) in the film were found to be higher than those of TPATPA-PPI 110 (26.0%) and TPATPA-CNPPI 111 (43.0%) in THF solution. The non-doped device of TPATPA-CNPPI 111 showed deep blue EL emission with CIEs of (0.16, 0.07) and maximum efficiencies of a CE of 19.58 cd A −1 , a PE of 17.84 l m W −1 , an EQE of 8.96%, an EUE of 73.40% and a small efficiency roll-off (Table 10).…”

“…23). 150 The PLQYs of TPATPA-PPI 110 (50.0%) and TPATPA-CNPPI 111 (61.0%) in the film were found to be higher than those of TPATPA-PPI 110 (26.0%) and TPATPA-CNPPI 111 PI-sulfone hybrid D-A-D HLCT characteristic PMSO 114 fluorophore with PI as a weak donor and sulfone as a moderate acceptor (Fig. 24).…”

“…Tetraphenylethene/triphenylethene (TPE/TPA-CN) is a classical building block for constructing fluorophores with aggregation induce enhancement (AIE) properties. 147,148 H. Zhang et al designed and synthesized a series of PI/tetraphenylethene derivatives having AIE and HLCT characteristics, pTPI 102 , mpCTPI 103 , ppCTI 104 , mTPI 105 , mmCTPI 106 , and pmCTPI 107 , 149 by connecting a TPE group with PI (Fig. 23).…”

Efficient M-shaped blue emitters having a high conjugation extent with improved roll-off efficiency

“…Third-generation organic emitters, namely thermally activated delayed fluorescence (TADF) 8 and hybridized local and charge-transfer (HLCT) 9,10 excited-state emitters, which render 100% exciton utilization efficiency (EUE) while avoiding noble metals, have been considered as potential candidates. The long exciton lifetime of TADF emitters (D–A molecules with small splitting energy) tends to cause serious efficiency roll-off under high current due to triplet–triplet annihilation (TTA), whereas short exciton lifetimes of HLCT emitters are beneficial to suppress exciton annihilation and thus improve efficiency roll-off.…”

Mechanoluminescence and Aggregation-Induced Emission in Bipolar Phenanthroimidazoles: Role of Positional Isomerization-Induced Switching Effect

“…Hybridized local and charge-transfer (HLCT) luminogens can convert dark triplet excitons to singlet excitons through reverse intersystem crossing (RISC) by reducing the single-triplet energy gap (Δ E ST ) and are potential candidates for harvesting efficient luminescence besides being phosphorescence emitters. , The HLCT materials consist of locally excited (LE) state and CT state characteristics. The LE component ensures relatively high fluorescence efficiency, and the CT component provides multistimuli-responsive fluorescence behavior, which may provide a new strategy to achieve high-efficient and high-contrast stimuli-responsive materials …”