Aromatic systems with two and three pyridine-2,6-dicarbazolyl-3,5-dicarbonitrile fragments as electron-transporting organic semiconductors exhibiting long-lived emissions

• Karolis Leitonas,
• Brigita Vigante,
• Dmytro Volyniuk,
• Audrius Bucinskas,
• Pavels Dimitrijevs,
• Sindija Lapcinska,
• Pavel Arsenyan and
• Juozas Vidas Grazulevicius

Beilstein J. Org. Chem. 2023, 19, 1867–1880, doi:10.3762/bjoc.19.139

• 10 000 cd m−2, electroluminescence ranging from blue to yellow, maximum current of 15 cd/A and higher EQE than 7%. Pyridine-3,5-dicarbonitrile-based TADF materials exhibit different visible light emission spectra (Figure 1). Recently, Chen and Lu reported two new orange-red/red TADF emitters composed

Thienothiophene-based organic light-emitting diode: synthesis, photophysical properties and application

• Recep Isci and
• Turan Ozturk

Beilstein J. Org. Chem. 2023, 19, 1849–1857, doi:10.3762/bjoc.19.137

• –voltage (J–L–V) graph and power efficiency (PE), external quantum efficiency (EQE), and electroluminescence curves are depicted in Figure 2 and Figure 3, respectively. Although DMB-TT-TPA (8) was synthesized and OLED performance was examined in our previous study [23], a different device architecture and

• efficiency–luminance, (b) external quantum efficiency–luminescence, (c) electroluminescence–wavelength characteristics of DMB-TT-TPA (8). Thermal gravimetric analyses (TGA) of DMB-TT-TPA (8). HOMO and LUMO diagrams calculated at the B3LYP/6-31G (d,p) level of theory. Synthesis of DMB-TT-TPA (8

The effect of dark states on the intersystem crossing and thermally activated delayed fluorescence of naphthalimide-phenothiazine dyads

• Liyuan Cao,
• Xi Liu,
• Xue Zhang,
• Jianzhang Zhao,
• Fabiao Yu and
• Yan Wan

Beilstein J. Org. Chem. 2023, 19, 1028–1046, doi:10.3762/bjoc.19.79

• harvesting efficiency of both the singlet and triplet excitons and thus a high quantum efficiency for the electroluminescence [13]. The TADF emission process involves the reverse intersystem crossing (rISC) from the triplet (T1) state to the emissive singlet (S1) state. A typical molecular structure motif

Ionic multiresonant thermally activated delayed fluorescence emitters for light emitting electrochemical cells

• Merve Karaman,
• Abhishek Kumar Gupta,
• Subeesh Madayanad Suresh,
• Tomas Matulaitis,
• Lorenzo Mardegan,
• Daniel Tordera,
• Henk J. Bolink,
• Sen Wu,
• Stuart Warriner,
• Ifor D. Samuel and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2022, 18, 1311–1321, doi:10.3762/bjoc.18.136

• were prepared using both DiKTa-OBuIm and DiKTa-DPA-OBuIm as active emitters showing green (λmax = 534 nm) and red (λmax = 656 nm) emission, respectively. Keywords: electroluminescence; light-emitting electrochemical cells; multiresonance; purely organic emitters; thermally activated delayed

• TADF emitter 2CzPN with imidazolium groups [16][17] (Figure 1a). The LEEC devices showed a maximum external quantum efficiency (EQEmax) of 0.39%, a maximum brightness (Bmax) of 13 cd m−2, and a peak electroluminescence (λEL) at 538 nm. The device performance suffered when the emissive layer was doped

• are ionic, in principle there is no need to incorporate additional mobile ions. A host–guest approach, using 1 wt % of DiKTa-DPA-OBuIm in DiKTa-OBuIm was also used, the latter acting as a host matrix for the former. The electroluminescence (EL) of the three device stacks is shown in Figure 5a. Similar

Post-synthesis from Lewis acid–base interaction: an alternative way to generate light and harvest triplet excitons

• Hengjia Liu and
• Guohua Xie

Beilstein J. Org. Chem. 2022, 18, 825–836, doi:10.3762/bjoc.18.83

• intermolecular mechanism, considered as post-synthesis of new luminescent compounds offers promising applications in sensing and electroluminescence by manipulating the frontier molecular orbital energy levels of organic conjugated materials, simply based on Lewis acid–base chemistry. Keywords: excitons

• showed the evident red-shift upon mixing the polymer with the Lewis acid (Figure 6a). This property was also successfully demonstrated in OLEDs to modify the electroluminescence (EL) characteristics (Figure 6b). In 2020, Yang et al. designed and synthesized a blue fluorescent material CzPA-F-PD (compound

• molecular synthesis. Lewis acid–base interactions found some promising applications in band gap engineering, photoluminescence, and electroluminescence. The in-depth study of the mechanisms of this phenomenon could inspire the innovation in cutting-edge researches beyond organic light-emitting diodes [29

Substituent effect on TADF properties of 2-modified 4,6-bis(3,6-di-tert-butyl-9-carbazolyl)-5-methylpyrimidines

• Irina Fiodorova,
• Tomas Serevičius,
• Rokas Skaisgiris,
• Saulius Juršėnas and
• Sigitas Tumkevicius

Beilstein J. Org. Chem. 2022, 18, 497–507, doi:10.3762/bjoc.18.52

• compounds. Efficient triplet harvesting in TADF compounds leads to internal quantum efficiencies up to 100% and electroluminescence yields exceeding 20% [3][4]. TADF OLEDs usually contain pure organic molecules, which avoid expensive noble metals and allow broad possibilities of molecular design. One of the

Comparative study of thermally activated delayed fluorescent properties of donor–acceptor and donor–acceptor–donor architectures based on phenoxazine and dibenzo[a,j]phenazine

• Saika Izumi,
• Prasannamani Govindharaj,
• Anna Drewniak,
• Paola Zimmermann Crocomo,
• Satoshi Minakata,
• Leonardo Evaristo de Sousa,
• Piotr de Silva,
• Przemyslaw Data and
• Youhei Takeda

Beilstein J. Org. Chem. 2022, 18, 459–468, doi:10.3762/bjoc.18.48

• profiles (intensity vs delay time) and spectra of 1 in a), b) Zeonex® and c, d) CBP matrix. The energies correspond to the maximum emission peaks. The characteristics of the OLED devices: a) electroluminescence spectra; b) current density-bias characteristics; c) EQE–current density characteristics; d

Effect of a twin-emitter design strategy on a previously reported thermally activated delayed fluorescence organic light-emitting diode

• Ettore Crovini,
• Zhen Zhang,
• Yu Kusakabe,
• Yongxia Ren,
• Yoshimasa Wada,
• Bilal A. Naqvi,
• Prakhar Sahay,
• Tomas Matulaitis,
• Stefan Diesing,
• Ifor D. W. Samuel,
• Wolfgang Brütting,
• Katsuaki Suzuki,
• Hironori Kaji,
• Stefan Bräse and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2021, 17, 2894–2905, doi:10.3762/bjoc.17.197

• 8.57 μs in 20 wt % DBFPO film (DBFPO = 2,8-bis(diphenylphosphine oxide)dibenzofuran). The device made from this material has a very high EQEmax of 30.3%, which decreases to 18.4% at 1000 cd m−2; the use of a stronger donor in TRZ-TPDICz results in a red-shift of the electroluminescence, compared to

• IndCzpTr-1 and IndCzpTr-2 (the electroluminescence maximum wavelength, λEL of 472 nm and 496 nm for IndCzpTr-1 and IndCzpTr-2, respectively, against λEL of 509 nm for TRZ-TPDICz). In our previous work, we presented the first example of a di-functionalized ICz-based emitter ICzTRZ [13][14], that presented

• electroluminescence, with λEL going from 449 nm for CzTRZ to 490 nm for 33TCzTTrz. In this work, we utilized a similar strategy to assess the change in optoelectronic properties and device performance of the compound DICzTRZ (Figure 2) compared to our recently reported ICzTRZ study [14]. We note that the effective

Catalyzed and uncatalyzed procedures for the syntheses of isomeric covalent multi-indolyl hetero non-metallides: an account

• Ranadeep Talukdar

Beilstein J. Org. Chem. 2021, 17, 2102–2122, doi:10.3762/bjoc.17.137

• -substituted amines 15, 18, and 20 [43]. Taking aniline as the pivotal moiety, it was coupled with isomeric bromoindoles 14 and 16 for the synthesis of the targeted products (Scheme 3b). Ethers Hongtao and co-workers also studied the electroluminescence properties of the 3,3’-bis(indolyl) ether derivatives 23

Synthesis, crystal structures and properties of carbazole-based [6]helicenes fused with an azine ring

• Daria I. Tonkoglazova,
• Anna V. Gulevskaya,
• Konstantin A. Chistyakov and
• Olga I. Askalepova

Beilstein J. Org. Chem. 2021, 17, 11–21, doi:10.3762/bjoc.17.2

• electroactive materials [52][53][54]. Carbazole-based [6]helicenes [42] and [7]helicenes [50] showed deep blue electroluminescence and have been investigated in OLED devices. Some carbazole-based [5]- and [6]helicenes have been used as visible light photoinitiators for cationic and radical polymerization [41

Synthesis and properties of quinazoline-based versatile exciplex-forming compounds

• Rasa Keruckiene,
• Simona Vekteryte,
• Ervinas Urbonas,
• Matas Guzauskas,
• Eigirdas Skuodis,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 1142–1153, doi:10.3762/bjoc.16.101

• photoluminescence and electroluminescence based on blue emissive quinazoline derivatives obtained through controlled acid protonation were employed in a single-layered white OLED with EQEs of 1.4% and 3% [9]. These reports proved that by using an asymmetric quinazoline acceptor, highly efficient TADF materials for

• peaked at the wavelength of 592 nm was observed for the solid mixture with the donor 4,4′,4″-tris[3-methylphenyl(phenyl)amino]triphenylamine (m-MTDATA) (Figure 7b). The combination of the sky-blue and orange exciplex emissions may result in white electroluminescence (EL). To check this assumption, a non

• electroluminescence obtained by mixing sky-blue and orange exciplexes (a). PL spectra of the film of 1, of exciplexes m-MTDATA:1/1:PO-T2T and phosphorescence spectrum of the solution of compound 1 in THF at 77 K (b). Phosphorescence was recorded with the delay of 50 ms after UV excitation (300 nm). EL spectra of OLED

Aryl-substituted acridanes as hosts for TADF-based OLEDs

• Naveen Masimukku,
• Dalius Gudeika,
• Oleksandr Bezvikonnyi,
• Ihor Syvorotka,
• Rasa Keruckiene,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 989–1000, doi:10.3762/bjoc.16.88

• -triphenylsilylphenylphosphine oxide (TSPO1) was used as hole blocking material, while the layer of 2,2',2"-(1,3,5-benzenetriyl)-tris(1-phenyl-1H-benzimidazole) (TPBi) was employed as the electron-transporting layer. Electroluminescence (EL) spectra of devices A–C and their external quantum efficiencies (EQE) are presented in

• calibrated photodiode and electroluminescence spectra were recorded with an Ocean Optics modular spectrometer [39]. Synthesis 2,7-Dibromo-10-ethyl-9,9-dimethyl-9,10-dihydroacridine (2). 2,7-Dibromo-9,9-dimethyl-9,10-dihydroacridine (0.7 g, 1.9 mmol) was dissolved in acetone (25 mL), tetrabutylammonium

• electroluminescence spectra of devices A–C recorded at 5 V (b); EQE versus current density plots (c), brightness and current density versus applied voltages plots (d) of the tested OLEDs; molecular structures of the organic derivatives used in the devices (e). Synthesis of acridan-based compounds 3–6. Reagents and

Recent advances in phosphorescent platinum complexes for organic light-emitting diodes

• Cristina Cebrián and
• Matteo Mauro

Beilstein J. Org. Chem. 2018, 14, 1459–1481, doi:10.3762/bjoc.14.124

• possibility to achieve theoretically 100% internal quantum efficiency in such devices. In the recent past, various classes of compounds have been reported, possessing a beautiful structural variety that allowed to nicely obtain efficient photo- and electroluminescence with high colour purity in the red, green

• ; electroluminescence; OLED; phosphorescence; platinum complexes; Introduction Photoactive TMCs have attracted enormous attention in the last two decades because of their peculiar photophysical and rich redox properties, which make them appealing from both fundamental research and technological applications points of

• nonradiative relaxation pathways. Schanze and co-workers have demonstrated, however, that it is possible to obtain satisfactory photo- and electroluminescence from trans-platinum(II) complex 1 bearing only monodentate ligands (Figure 1) [19]. In this derivative, the MC states were efficiently destabilized by

Two novel blue phosphorescent host materials containing phenothiazine-5,5-dioxide structure derivatives

• Feng-Ming Xie,
• Qingdong Ou,
• Qiang Zhang,
• Jiang-Kun Zhang,
• Guo-Liang Dai,
• Xin Zhao and
• Huai-Xin Wei

Beilstein J. Org. Chem. 2018, 14, 869–874, doi:10.3762/bjoc.14.73

• (≥170°), fast response (1 μs scale), high luminous efficiency, low drive voltage (3–10 V), thickness (less than 2 mm), lightweightness and flexibility [2][3][4][5][6]. Compared with traditional fluorescence OLEDs which only utilize singlet (25%) excitons for electroluminescence, PhOLEDs can

D–A–D-type orange-light emitting thermally activated delayed fluorescence (TADF) materials based on a fluorenone unit: simulation, photoluminescence and electroluminescence studies

• Lin Gan,
• Xianglong Li,
• Xinyi Cai,
• Kunkun Liu,
• Wei Li and
• Shi-Jian Su

Beilstein J. Org. Chem. 2018, 14, 672–681, doi:10.3762/bjoc.14.55

• different configurations have a serious effect on the photoluminescence and electroluminescence performance according to the change in singlet–triplet splitting energy (ΔEST) and excited state geometry. This indicates that a better configuration design can reduce internal conversion and improve triplet

• previously limited by the statistic rule of spin multiplicity. For conventional fluorescent materials, only singlet excitons are involved in electroluminescence, leading to a theoretical maximal internal quantum efficiency (IQEmax) of 25% and a theoretical maximal external quantum efficiency (EQEmax) of 5

• %, when assuming the out-coupling efficiency to be 20%. On the other hand, phosphorescent materials could utilize triplet excitons in electroluminescence processes to achieve 100% IQEmax [2][3]. However, the utilization of metals like iridium and platinum, which are expensive and nonrenewable, inevitably

Recent advances on organic blue thermally activated delayed fluorescence (TADF) emitters for organic light-emitting diodes (OLEDs)

• Thanh-Tuân Bui,
• Fabrice Goubard,
• Malika Ibrahim-Ouali,
• Didier Gigmes and
• Frédéric Dumur

Beilstein J. Org. Chem. 2018, 14, 282–308, doi:10.3762/bjoc.14.18

• popularized by Chihaya Adachi since 2012. In this review, we proposed to focus on the recent advances in the molecular design of blue TADF emitters for OLEDs during the last few years. Keywords: blue; electroluminescence; emitter; OLED; TADF; Introduction Since the pioneering works of Tang and VanSlyke in

• . The decay time of the delayed component of luminescence was determined as being 2.36 μs and 6.71 μs for B1 and B2, respectively. When evaluated in multilayered OLEDs, a blue electroluminescence (EL) peaking at 466 nm and 479 nm, an external quantum efficiency (EQE) of 15.1% and 16.0% were obtained for

Synthesis and photophysical characteristics of polyfluorene polyrotaxanes

• Aurica Farcas,
• Giulia Tregnago,
• Ana-Maria Resmerita,
• Pierre-Henri Aubert and
• Franco Cacialli

Beilstein J. Org. Chem. 2015, 11, 2677–2688, doi:10.3762/bjoc.11.288

• in an electroluminescence configuration cell. The present study is significantly valuable and informative as a method to built new conjugated polyrotaxanes by using permodified CD derivatives. Development of new polyrotaxane architectures should be beneficial especially in the field of materials for

Conjugated polymers containing diketopyrrolopyrrole units in the main chain

• Bernd Tieke,
• A. Raman Rabindranath,
• Kai Zhang and
• Yu Zhu

Beilstein J. Org. Chem. 2010, 6, 830–845, doi:10.3762/bjoc.6.92

• characteristic properties of the polymers are described. Potential applications in the field of organic electronic materials such as light emitting diodes, organic solar cells and organic field effect transistors are discussed. Keywords: conjugated polymer; diketopyrrolopyrrole; electroluminescence

Synthesis of 2,3,6,7-tetrabromoanthracene

• Christian Schäfer,
• Friederike Herrmann and
• Jochen Mattay

Beilstein J. Org. Chem. 2008, 4, No. 41, doi:10.3762/bjoc.4.41

• , electroluminescence) and several reviews have been published so far [1][2][3]. Anthracenes may be readily functionalized in positions 9 and 10 due to their exceptional reactivity. The outer rings, however, can not be functionalized easily. There are some anthracene compounds available with one or two substituents at