China
Africa
Explore chapters and articles related to this topic
Solid-State Organic Photovoltaics: A Review of Molecular and Polymeric Devices
Published in Sun Sam-Shajing, Sariciftci Niyazi Serdar, Organic Photovoltaics, 2017
Arias et al. [107–109] reported the performance of photovoltaic devices based on blends of poly(9,9′-dioctylfluorene-co-benzothiadiazole) (F8BT) and poly(9,9′-dioctylfluorene-co-bis-N,N′-(4-butylphenyl)-bis-N,N′-phenyl-1,4-phenylenediamine) (PFB). Polyfluorene and its copolymers have emerged as leading candidates for polymer LEDs and displays due to attractive optical and chemical properties such as chemical tunability via copolymerization, high fluorescence quantum yield in neat films, and trap-free charge transport [110]. Polyfluorene also exhibits superior thermal stability and photostability vis-à-vis PPV, suggesting its use in solar cells where stability has been problematic. PFB is a copolymer with alternating fluorene and triphenylamine subunits that has been used as a hole-transporting layer. Triphenylamines have excellent hole transport properties and have been used in photoconductors and LEDs. Time-of-flight mobility measurements of PFB performed by Redecker et al. have shown hole mobilities of up to 2×10−3 cm2/Vs [111]. F8BT, on the other hand, has a high electron affinity (3.53 eV) [108]. Because of the large difference between the highest occupied molecular orbital (HOMO; 0.8 eV) and LUMO (1.24eV) levels of the two polymers, photoinduced charge transfer should be strong in a blend of PFB and F8BT.
Polyimides as Langmuir-Blodgett Films
Published in Malay K. Ghosh, K. L. Mittal, Polyimides Fundamentals and Applications, 2018
Mitsumasa Iwamoto, Masa-aki Kakimoto
The triad photodiode systems using polyimide LB films, in which triphenylamines, tetra-phenylporphyrin (TPP), and aromatic polyimide units were used as D, S, and A, respectively, were successfully prepared. Triphenylamines are known to have high electron-donating ability and high hole mobility. Furthermore, substituents that control the electron density of the nitrogen atom can be readily introduced into the benzene ring. Poly(amic acid)s (3l) that had triphenylamine unit and aliphatic tetracarboxylic dianhydride were used as LB films.
Star-shaped Pd(II) and Pt(II) complexes containing C3-symmetric conjugated thiophenes: Synthesis, characterization, and chemical reactions with organic unsaturated molecules
Published in Journal of Coordination Chemistry, 2022
Hee Kwon Park, Min Gyu Ham, Yong-Joo Kim, Katsuhiko Takeuchi, Jun-Chul Choi
The reactions for trinuclear complexes containing thiophene derivatives with triazinyl or triphenylamine cores afforded the complexes shown in Scheme 4. 1H-NMR spectra of star-shaped trinuclear Pd(II)/Pt(II) complexes (1 − 7) containing C3-symmetric ligands (1-, 3-, and 5-thiophene-substituted benzene, triazine, and triphenylamine) exhibited suitable integration ratios in the aromatic core region (for all three ligands) and tertiary phosphine region (for metal moieties). Supporting symmetric equivalence of PR3 ligand, the 31P NMR spectra of the complexes exhibited a singlet peak, or a singlet peak flanked with Pt satellite signals. The molecular structure of 6 in Figure 1 demonstrates a C3-symmetric triazine-thiophene plane containing three vertical bis(phosphine) Pt(II) moieties. Crystallographic data are summarized in Table 1.
Layered bifuncational Co(II) coordination polymer for photodegradation of organic dyes and anti-osteoporosis activity by activating wnt/β-catenin/PPARγ pathway in BMSCs
Published in Inorganic and Nano-Metal Chemistry, 2020
Zhi-Yong Cheng, Ming Ji, Yong Yang, Xue-Jian Wu
In summary, we have successfully prepared a new layered coordination polymer by using a light-harvesting triphenylamine type organic ligand 4,4′,4″-s-triazine-2,4,6-triyltribenzoic acid in the mixed solvent of water and DMF. Furthermore, complex 1 has significant photocatalytic activity under visible light for the degradation of organic dyes such as rhodamine B (RhB), methylene blue (MB) as well as methyl orange (MO) assisted by H2O2. In the biological study, the anti-osteoporosis activity of complex 1 was evaluated. The BMSCs were isolated from the mice and treated with complex 1 and ligand. The Annexin V-FITC/PI method was utilized to test the inhibitory effect of complex 1 on the BMSCs apoptosis, which is closely related with the osteoporosis. The results indicated that complex 1 has protective effect in BMSCs by inhibiting the level of apoptotic cells, but no the ligand. Next, the results of the RT-PCR revealed that complex 1 significantly up-regulated the expression level of the wnt, β-catenin and PPARγ. All the results above indicated complex 1 exert anti-osteoporosis activity through activating the wnt/β-catenin/PPARγ pathway. The molecular docking simulation confirms that the possible binding interactions are normally formed between the oxygen atoms on the ligand and the polar atoms on the protein, while the nitrogen atoms on the ligand do not exhibit enough activity.
Imidazole derivatives for efficient organic light-emitting diodes
Published in Journal of Information Display, 2020
Shaofeng Ye, Shaoqing Zhuang, Biao Pan, Runda Guo, Lei Wang
A series of aromatically substituted phenanthro[9,10-d]imidazole (PI) fluorophores at the C6 and C9 positions were researched on [39]. The C6 and C9 modifications had positive influences on the thermal properties of the new materials. The theoretical calculations suggest that the C6 and the C9 positions of PI are electronically different. Theoretical and experimental evidences of intramolecular charge transfer (ICT) between two identical moieties attaching to the C6 and the C9 positions were observed. The photophysical properties of the fluorophores were greatly influenced by the size and conjugation extent of the substituents as well as by the linking steric hindrance. It was found that the C6 and C9 positions afforded a moderate conjugated extension compared to the C2 modification. Moreover, the ICT characteristics of the new fluorophores increased along with the size of the substituted aromatic group, and were partially influenced by the steric hindrance, with the anthracene and pyrene derivatives having the strongest ICT-excited properties. The EL performances of the fluorophores as host emitters or dopants in OLEDs were evaluated. Then the donor-π-acceptor approach was used to design TPA-BPI, PATPA, BPA-BPI, and TPA-TPI molecules, using PI as the acceptor and triphenylamine (TPA) as the donor, by connecting them with benzene or thiophene [40]. The intersection of the lowest unoccupied molecular orbital (LUMO) and the highest occupied molecular orbital (HOMO) on the imidazole ring would contribute to a balanced charge transfer (CT) and would facilitate the CT process upon excitation.