A dual-locked triarylamine donor enables high-performance deep-red/NIR thermally activated delayed fluorescence organic light-emitting diodes

Abstract

Deep-red/near-infrared (DR/NIR) organic light-emitting diodes (OLEDs) have attracted a great deal of attention due to their widespread application fields, such as night-vision devices, optical communication, and information-secured displays. However, most...

Asymmetric donor–acceptor–host red thermally activated delayed fluorescent emitter for high-efficiency organic light emitting diodes

“…This is due to the lack of rigid stereoscopic groups, which are crucial for effectively avoiding the quenching effect in the aggregated state. 48 The transient PL decay of the doped film was studied (Fig. 3b and c).…”

Recent advances of organic emitters in deep‐red light‐emitting electrochemical cells

“…Now the AIE OLMs showed high performance in deep‐red LECs, and the potential of the AIE molecular structure could be successfully adapted to TADF and other useful strategies. In 2023, Wang et al prepared a TADF deep‐red OLED active material with AIE characteristic, by which they fabricated high‐performance device with a EQE of 21.3% at 716 nm [69]. The molecule used two bulky fluorene‐locks as donors, which was designed to make HOMO and LUMO separate and overlap properly, balancing the TADF process and PLQY efficiency.…”

Introducing Internal Host Component to Thermally Activated Delayed Fluorescence Emitter for Efficient NIR Nondoped Organic Light-Emitting Diodes

“…Organic light-emitting diodes (OLEDs) have been receiving mounting interest due to thermally activated delayed fluorescence (TADF) emitters being an emerging family of emitters for organic light-emitting diodes (OLEDs) that demonstrate the attractive capability of fully harvesting both singlet and triplet excitons free of any noble metals. − In the past decade, significant progress has been made in TADF-OLEDs in the visible region. − In contrast, the development of TADF-OLEDs approaching the near-infrared (NIR) region is significantly lagging behindthere have been only a few reports showing far inferior efficiency, although NIR electroluminescence (EL) permits promising unique applications such as night-vision readable marking, medical therapy, and telecommunication. − The mainstream route is to directly construct electron-donor (D)-electron-acceptor (A)-type TADF emitters that intrinsically emit NIR photons. − For example, Bronstein et al developed a TADF emitter based on a NIR prototypical emitter (APDC-DTPA) by strategically replacing a D group (triphenylamine) with an A group (cyan), affording NIR emission (e.g., peaking at 763 nm in toluene); however, this approach has fallen short in the device efficiency due to the serious energy loss associated with the reduced optical band gap, hampering potential applications . Furthermore, in terms of molecular designs, such candidates of D and A building block pairs that are strong enough for NIR band gaps are very limited, which poses great challenges for developing intrinsically NIR TADF emitters. − …”