Aggregation‐induced emission luminogens for organic light‐emitting diodes with a single‐component emitting layer

Abstract

Organic light‐emitting diodes (OLEDs) have garnered increasing attention as a promising candidate for application in next‐generation displays and solid‐state lighting devices. The doping technique commonly used to fabricate light‐emitting layers (EMLs) of OLEDs disperses the emitting material in a host matrix to mitigate aggregation‐induced quenching (ACQ). Alternatively, owing to their high efficiency and ease of manufacture, nondoped OLEDs have been developed as a substitute for doped OLEDs. When fabricating nondoped OLEDs, it is essential to suppress the ACQ effect in the EML and efficiently utilize the generated excitons for radiative decay. Since the discovery of aggregation‐induced emission (AIE) by Tang et al., significant work has been done to improve the stability and efficiency of nondoped OLEDs based on fluorescent AIE luminogens (AIEgens). Fluorescent AIEgens, synthesized using various molecular frameworks, such as silole, tetra/triphenylethylene, tetraphenylpyrazine, and tetraphenylbenzene, exhibit high photoluminescence quantum yields in the solid state. Therefore, many studies have reported that fluorescent AIEgen‐based OLEDs have excellent external quantum efficiency and exhibit emission at various wavelengths, including deep‐blue/blue/green emission. With the development of fluorescent AIEgens, delayed fluorescent AIEgens with efficient triplet utilization through reverse intersystem crossing and AIE properties have been adopted as ideal emitters and used in nondoped OLEDs. This review systematically discusses and summarizes recent reports on the development of AIEgens for nondoped OLEDs by grouping them into fluorescent and delayed fluorescent AIEgens. The purpose of this review is to provide deep insights into the design of novel AIEgens for high‐performance nondoped OLEDs.

Simple excited-state modification toward a deep-blue hybridized local and charge-transfer (HLCT) fluorophore and non-doped organic light-emitting diodes

“…The lower PLQY of the DTPA2F film than that of DCZ2F should be attributed to the increased nonradiative channels of the excited state caused by the motion of benzene units of triphenylamine. 53 Low-temperature fluorescence and phosphorescence spectra were carried out to measure the energy levels of S 1 and T 1 . According to the emission peaks, S 1 s and T 1 s can be estimated to be 3.26 and 2.41 eV for DCZ2F, and 3.04 and 2.38 eV for DTPA2F, respectively.…”

Metal-free polycyclotrimerization of trimethylsilyl-protected diynes: a facile strategy toward regioregular hyperbranched polyarylenes

“…47 During the past two decades, AIE luminogens have drawn much interest due to their unique luminescence properties and wide applications. 48–54 Nevertheless, HBPs with AIE properties have been rarely reported. 55–60…”

“…47 During the past two decades, AIE luminogens have drawn much interest due to their unique luminescence properties and wide applications. [48][49][50][51][52][53][54] Nevertheless, HBPs with AIE properties have been rarely reported. [55][56][57][58][59][60] Given that TPE is a typical AIE molecule, the TPE-containing hb-PAs are expected to show AIE activities.…”

An overview on AIEgen‐decorated porphyrins: Current status and applications

“…Generally, AIEgens are not emissive in the solution because the free‐rotation of phenyl groups deactivates the photoluminescence intensity, whereas such AIEgens can increase the photoluminescence intensity drastically in the solid state owing to the restriction of intramolecular motion. Thus, over the last two decades, many papers have been published based on the AIEgen containing materials for solar cells, [ 36–38 ] organic light emitting diodes (OLEDs), [ 39–42 ] sensing applications, [ 43–47 ] photocatalysis, [ 48 ] and biomedical fields. [ 49–51 ] On the contrary, very limited papers were published based on the AIEgen‐decorated porphyrins for fluorescence bioimaging, photodynamic therapy (PDT), photocatalytic hydrogen evolution (PHE), solid state photoluminescence, electrochemiluminescence (ECL), and self‐assembled studies.…”