Constructing Soluble Anthracene‐Based Blue Emitters Free of Electrically Inert Alkyl Chains for Efficient Evaporation‐ and Solution‐Based OLEDs

Abstract

Anthracene derivatives are one of the most promising blue emitters employed in organic light‐emitting devices (OLEDs) because of their electrochemical and thermal stabilities. However, their high crystallinity owing to their large π‐planar structures severely impedes the progress in the development of solution‐based systems. In this work, we developed two types of highly soluble multifunctional anthracene derivatives terminated with ortho‐biphenyl and triphenylamine moieties and showed high solubility in general organic solvents such as toluene, tetrahydrofuran, and cyclohexanone at high concentrations (>10 mg mL−1), and showed blue emission with a peak wavelength of ∼465 nm and a high photoluminescence quantum yield that ranges up to 81 %. Notably, these emitters are suitable for fabricating both evaporation‐ and solution‐based systems. The evaporation‐based system OLED achieved a high external quantum efficiency (EQE) of 5.4 %. While the solution‐processed system realized 4.8 %, exhibiting the best performance among the anthracene‐based solution‐processed OLEDs so far.

Recent Advances in Triplet–Triplet Annihilation-Based Materials and Their Applications in Electroluminescence

“…By changing benzene to the orthobiphenyl moiety, two blue TTA emitters (53 and 54) were designed and synthesized. 99 These two compounds showed good solubilities in common organic solvents and provided intense blue emissions (460−462 nm) with high PLQYs (81% and 73%) in the solid state. More importantly, they could be adopted as the emitters in both evaporation-and solution- Subsequently, by introducing the TPE unit into another side of anthracene, a blue TTA emitter (55) with the AIE property was developed.…”

“…In particular, the CE and EQE of the 52 -based device still remained as high as 9.09 cd A –1 and 6.97% at a luminance of 1000 cd m –2 , demonstrating the low-efficiency roll-offs of the device. By changing benzene to the ortho -biphenyl moiety, two blue TTA emitters ( 53 and 54 ) were designed and synthesized . These two compounds showed good solubilities in common organic solvents and provided intense blue emissions (460–462 nm) with high PLQYs (81% and 73%) in the solid state.…”

Novel Fused Core Chromophore Incorporating Spirofluorene and Anthracene Groups for Sky-Blue Emission and Solution-Processed White Devices

“…Column refinement under EA: hexane = 1:10 eluent was proceeded after evaporation of product in the organic layer in order to obtain (6) compounds as yellow powder. 1 [3,4]-5-bromonapthalene (7) Spiro-fluorene [3,4]naphthalene (0.5 g, 1.20 mmol) was dissolved in chloroform 10 mL, and bromine (0.06 mL, 1.11 mmol) was slowly added at 0 • C. The solution was stirred for 3 h. By adding acetone, the mixture was quenched, and then extracted using chloroform and water. Using MgSO 4 for removing a small amount of water in the organic layer.…”

“…The following supporting information can be downloaded at: https: //www.mdpi.com/article/10.3390/app131810154/s1, Table S1: Time-dependent density functional theory calculations; Figure S1: DSC curve (a) TP-AFF-TP, (b) TP-ASF; Figure S2: Device lifetime of TP-AFF-TP and TP-ASF; Figure S3: 1 H-NMR Spectrum of 5-Bromoanthraquinone (1); Figure S4: 1 H-NMR Spectrum of 1-Bromoanthracene (2); Figure S5: 1 H-NMR Spectrum of 1-(2-Bromophenyl)anthracene (4); Figure S6: 1 H-NMR Spectrum of 2,7-Dibromo-spiro-fluorene [3,4]naphthalene (5); Figure S7: 1 H-NMR Spectrum of Spiro-fluorene [3,4]naphthalene (6); Figure S8: 1 H-NMR Spectrum of Spiro-fluorene [3,4]-5-bromonapthalene (7); Figure S9: 1 H-NMR Spectrum of 2,7-Bis-[1,1';3',1"]terphenyl-spiro-fluorene [3,4]naphthalene (TP-AFF-TP); Figure S10: 13 C-NMR Spectrum of 2,7-Bis-[1,1';3',1"]terphenyl-spiro-fluorene [3,4]naphthalene (TP-AFF-TP); Figure S11: 1 H-NMR Spectrum of Spiro-fluorene [3,4]…”

“…The significant band gap of blue-emitting materials engenders a mismatched recombination zone for electrons and holes, resulting in diminished EL efficiency and a shorter operational lifespan for OLED devices. Over time, an array of blue-light emitters has been extensively explored, including derivatives based on anthracene [6][7][8][9][10], fluorine [11], pyrene [12], and di(styryl)arylene [13] with the aim of enhancing their electroluminescent properties. These chromophores have been extensively studied as emitting materials, and the structures that could have been developed using a single chromophore have reached their limits.…”