High-performance blue OLED using multiresonance thermally activated delayed fluorescence host materials containing silicon atoms

Abstract

We report three highly efficient multiresonance thermally activated delayed fluorescence blue-emitter host materials that include 5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene (DOBNA) and tetraphenylsilyl groups. The host materials doped with the conventional N7,N7,N13,N13,5,9,11,15-octaphenyl-5,9,11,15-tetrahydro-5,9,11,15-tetraaza-19b,20b-diboradinaphtho[3,2,1-de:1’,2’,3’-jk]pentacene-7,13-diamine (ν-DABNA) blue emitter exhibit a high photoluminescence quantum yield greater than 0.82, a high horizontal orientation greater than 88%, and a short photoluminescence decay time of 0.96–1.93 μs. Among devices fabricated using six synthesized compounds, the device with (4-(2,12-di-tert-butyl-5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracen-7-yl)phenyl)triphenylsilane (TDBA-Si) shows high external quantum efficiency values of 36.2/35.0/31.3% at maximum luminance/500 cd m−2/1,000 cd m−2. This high performance is attributed to fast energy transfer from the host to the dopant. Other factors possibly contributing to the high performance are a T1 excited-state contribution, inhibition of aggregation by the bulky tetraphenylsilyl groups, high horizontal orientation, and high thermal stability. We achieve a high efficiency greater than 30% and a small roll-off value of 4.9% at 1,000 cd m−2 using the TDBA-Si host material.

Intermolecular lithium bonding between different components upon mixing simultaneously enhances the thermal and electrical properties of an amorphous organic semiconductor material

“…20–23 Given that lithium is one of the most important elements in organic electronic devices, the peculiar characteristics of lithium bonding are expected to have significant potential in organic electronics applications. Additionally, efforts to develop the new host material rather than the mixing have been reported continuously to improve the thermal stability and electric properties, 24–26 but the cost and time to synthesize more regulated molecular structures before forming the material are a basic problem, and by-products generated despite efforts for high yields are also unavoidable. The mixing using the physical vapor deposition (PVD) method can easily yield macroscopically homogenous, anisotropic materials.…”

Restraint of Nonradiative Recombination via Modulation of n-Phase Distribution through Interfacial Lithium Salt Insertion for High-Performance Pure-Blue Perovskite LEDs

“…Quasi -two-dimensional ( quasi -2D) perovskite materials have been widely used in perovskite light-emitting diodes (PeLEDs), owing to their excellent optical properties, adjustable band gaps, solution processability, high color purity, and superior carrier transportation. − Notably, near-infrared and green PeLEDs have achieved external quantum efficiencies (EQEs) exceeding 20% since their initial demonstration in 2014, − positioning them as competitive alternatives to organic light-emitting diodes (OLEDs) and quantum-dot light-emitting diodes (QLEDs) . However, blue PeLEDs are encountering several challenges, such as uneven distribution of n -phase ( n represents layer number of the perovskite), serious nonradiative recombination, imbalanced charge injection, and poor conductivity, which have restricted their commercial application. − Among of them, nonradiative recombination, including Auger recombination, trap-assisted recombination, electron–phonon coupling, and interface-induced recombination, − exist both in perovskite film and at interfaces.…”

Unraveling Degradation Processes and Strategies for Enhancing Reliability in Organic Light-Emitting Diodes

“…This growth is driven by the rising adoption of OLED technology, advancements in display technology, and increasing consumer demand for high-quality displays. Researchers are exploring innovative strategies to enhance efficiency and mitigate degradation in organic light-emi ing diodes (OLEDs) [8]. A notable approach involves the utilization of thermally activated delayed fluorescence (TADF) materials, capable of converting less efficient triplet excitons into more efficient singlet excitons.…”

“…Overall, numerous promising approaches to enhancing OLED efficiency, including TADF, TTA, and TED-TADF, are showing significant potential, with ongoing research aimed at refining techniques for further improvements. Researchers are exploring innovative strategies to enhance efficiency and mitigate degradation in organic light-emitting diodes (OLEDs) [8]. A notable approach involves the utilization of thermally activated delayed fluorescence (TADF) materials, capable of converting less efficient triplet excitons into more efficient singlet excitons.…”