Multiplying the efficiency of red thermally activated delayed fluorescence emitter by introducing intramolecular hydrogen bond

Red-shift emission and rapid up-conversion of B,N-containing electroluminescent materialsviatuning intramolecular charge transfer

“…Three designed boron-carbazole containing emitters, namely, BN-AC, BN-PXZ and BN-PZ, were synthesized by a nucleophilic aromatic substitution reaction and tandem electrophilic arene borylation (Experimental Section and Scheme S1 in the ESI †). These emitters have been characterized by 1 H NMR, 13 C NMR, and time of flight mass spectrometry (Fig. S1-S9, ESI †).…”

“…[4][5][6][7][8][9] The most widespread TADF molecular design strategy is the use of highly distorted donor-acceptor (D-A) structures. [10][11][12][13] The twisted D-A framework accompanied by the intramolecular charge transfer (ICT) characteristic allows TADF materials to easily exhibit full-color emission, which is essential for color displays, white lighting, imaging applications, etc. [14][15][16] In 2016, Hatakeyama and co-workers developed novel PAHs containing boron (B) and nitrogen (N) atoms.…”

Unveiling the In Situ and Solvent Polymerization Engineering for Highly Efficient and Flexible Thermally Activated Delayed Fluorescence Organic Light-Emitting Diodes

“…Unlike the first generation of fluorescent materials with 25% lower exciton utilization and the second generation of phosphorescent materials that use heavy metals to increase spin–orbit coupling, the third generation of TADF materials have become the “new star” in the OLED field with their effective reverse intersystem crossing (RISC) to achieve 100% internal quantum efficiency and environmental friendliness without the use of any heavy metals. Although many TADF emitters using the vacuum vapor deposition process for device preparation have been reported so far, − the solution-processing technique for device preparation has more significant advantages in terms of low cost, low energy consumption, low consumables, and simple devices compared to vacuum vapor deposition. − In this context, polymeric materials are receiving more and more attention due to their good solubility and morphological stability suitable for solution-processable as well as flexible device preparation.…”

Equilibrating the key parameters of thermally activated delayed fluorescence emitters towards efficient red/near-infrared OLEDs

“…39–43 For example, Qiao et al demonstrated a high photoluminescence quantum yield ( Φ PL ) of 97.4% (dpTPAAP) with an emission peak at 624 nm, 33 Xu and co-workers showed an excellent Φ PL of 90% ( p CNQ–TPA) with an emission peak even at 691 nm, 44 and Ma et al revealed a very high oscillator strength ( f ) of 0.72 (DTPS-PT) for the S 0 → S 1 excitations, 45 while the drawbacks are a relatively large Δ E ST and low k RISC resulting in an inferior device efficiency. 46–48 With this in mind, precisely regulating the TADF parameters of triarylamine derivative based D–A type red/NIR emitters may offer a reliable means to further improve their electroluminescence (EL) performances.…”

“…Notably, all these devices demonstrate obvious efficiency roll-off at high brightness (Table 2), which can be ascribed to the typical triplet–triplet annihilation mechanism. 46 In addition, non-doped devices by employing the two new emitters were fabricated as well, and the emission peaks were successfully extended to the NIR region (∼780 nm) together with a considerable EQE max of around 1% (Fig. S33, ESI†).…”