| 1. |
Kazuhiro Nakamura, Kenshiro Matsuda, Rui Xiaotian, Minori Furukori, Satoshi Miyata, Takuya Hosokai, Kosuke Anraku, Kohei Nakao, Ken Albrecht, Effects of halogen atom substitution on luminescent radical: A case study on tris(2,4,6-trichlorophenyl)methyl radical-carbazole dyad, Faraday Discussions, 10.1039/D3FD00130J, 250, 192-201, 2023.09. |
| 2. |
Hiroki Ikebe, Kohei Nakao, Eri Hisamura, Minori Furukori, Yasuo Nakayama, Takuya Hosokai, Minlang Yang, Guanting Liu, Takuma Yasuda, Ken Albrecht, Thermally Activated Delayed Fluorescence Carbazole-Triazine Dendrimer with Bulky Substituents, Aggregate, 10.1002/agt2.405, 2023.08. |
| 3. |
Luca M. Cavinato, Keiko Yamaoka, Sophia Lipinski, Vladimir Calvi, Dominique Wehenkel, Richard van Rijn, Ken Albrecht*, Rubén D. Costa, Dendri-LEC Family: Establishing the Bright Future for Dendrimer Emitters in Traditional and Graphene-Based Light-Emitting Electrochemical Cells, Advanced Functional Materials, 10.1002/adfm.202302483, 2023.06, A rational implementation and optimization of thermally activated delayed fluorescent (TADF) dendrimer emitters in light-emitting electrochemical cells (LECs) sets in the Dendri-LEC family. They feature outstanding stabilities (90/1050 h for green/yellow devices) that are comparable to the best green/yellow Ir(III)-complexes (450/500 h) and conjugated polymers (33/5500 h), while offering benefits of low-cost synthesis and easy upscaling. In particular, a fundamental molecular design that capitalizes on exchanging peripheral substituents (tert-butyl vs methoxy) to tune photophysical, electrochemical, morphological, and ion conductivity features in thin films is rationalized by temperature-dependent steady-state and time-resolved emission spectroscopy, cyclic voltammetry, atomic force microscopy, and electrochemical impedance spectroscopy techniques. Herein, a TADF mechanism associated to a reduced photoluminescence quantum yield, but an enhanced electrochemical stability and ion conductivity enables to clarify the reduced device efficiency and brightness (4.0 lm W−1@110 cd m−2 vs 3.2 lm W−1@55 cd m−2) and increased stability (90 vs 1050 h) upon using methoxy groups. What is more, this substitution enables an excellent compatibility with biogenic electrolytes keeping device performances (1.9 lm W−1@35 cd m−2 and 1300 h), while graphene-devices achieve on par figures to traditional indium–tin oxide-devices. Overall, this work establishes the bright future of dendrimer emitters toward highly stable and truly sustainable lighting sources.. |
| 4. |
Rui Xiaotian, Wataru Ota, Tohru Sato, Minori Furukori, Yasuo Nakayama, Takuya Hosokai, Eri Hisamura, Kazuhiro Nakamura, Kenshiro Matsuda, Kohei Nakao, Andrew P. Monkman, Ken Albrecht, Carbazole-Dendronized Luminescent Radicals, Angewandte Chemie International Edition, 10.1002/anie.202302550, 2023.03, A series of carbazole-dendronized tris(2,4,6-trichlorophenyl)methyl (TTM) radicals have been synthesized. The photophysical properties of dendronized radicals up to the fourth generation were compared systematically to understand how structure–property relationships evolve with generation. The photoluminescence quantum yield (PLQY) was found to increase with the increasing generation, and the fourth generation (G4TTM) in cyclohexane solution showed a PLQY as high as 63 % at a wavelength of 627 nm (in the deep-red region) from the doublet state. The dendron modification strategy also showed a blue-shift of the emission on increasing the generation number, and the photostability was also increased compared to the bare TTM radical.. |
| 5. |
Kenshiro Matsuda, Xiaotian Rui, Kazuhiro Nakamura, Minori Furukori, Takuya Hosokai, Kosuke Anraku, Kohei Nakao, Ken Albrecht, Photostability of luminescent tris(2,4,6‐trichlorophenyl)methyl radical enhanced by terminal modification of carbazole donor, Chemical Communications, 10.1039/D2CC04481A, 2022.11. |
| 6. |
Jun WATANABE, Masaki FURUSAWA, Kosuke NAKAMOTO, Yuchao SUN, Masatoshi TASHIMA, Keiko YAMAOKA, Seiko FUJIWARA, Han Seul KIM, Shigeto OKADA, Ken ALBRECHT , 3,6-Diphenyltetrazine as Cathode Active Material for Sodium Ion Batteries, Electrochemistry, 10.5796/electrochemistry.22-00100, 2022.11. |
| 7. |
Ken Albrecht, Eri Hisamura, Minori Furukori, Yasuo Nakayama, Takuya Hosokai, Kohei Nakao, Hiroki Ikebe, Akira Nakayama, Thermally activated delayed fluorescence of carbazole-benzophenone dendrimers with bulky substituents, POLYMER CHEMISTRY, 10.1039/d2py00255h, 13, 16, 2277-2284, 2022.02. |
| 8. |
Ken Albrecht, Maki Taguchi, Takamasa Tsukamoto, Tatsuya Moriai, Nozomi Yoshidaa, Kimihisa Yamamoto, Poly-phenylene jacketed tailor-made dendritic phenylazomethine ligand for nanoparticle synthesis, CHEMICAL SCIENCE, 10.1039/d1sc05661a, 13, 20, 5813-5817, 2022.03, Synthesizing metal clusters with a specific number of atoms on a preparative scale for studying advanced properties is still a challenge. The dendrimer templated method is powerful for synthesizing size or atomicity controlled nanoparticles. However, not all atomicity is accessible with conventional dendrimers. A new tailor-made phenylazomethine dendrimer (DPA) with a limited number of coordination sites (n = 16) and a non-coordinating large poly-phenylene shell was designed to tackle this problem. The asymmetric dendron and adamantane core four substituted dendrimer (PPDPA16) were successfully synthesized. The coordination behavior confirmed the accumulation of 16 metal Lewis acids (RhCl3, RuCl3, and SnBr2) to PPDPA16. After the reduction of the complex, low valent metal nanoparticles with controlled size were obtained. The tailor-made dendrimer is a promising approach to synthesize a variety of metal clusters with desired atomicity.. |
| 9. |
Kenji Takada, Mari Morita,Takane Imaoka, Junko Kakinuma, Ken Albrecht, Kimihisa Yamamoto, Metal atom–guided conformational analysis of single polynuclear coordination molecules, Science Advances, 10.1126/sciadv.abd9887, 7, 32, eabd9887, 2021.08.  |
