Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:6.2.1.1 (ACS)
 78,556 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A series of 3,3'-bicarbazole (mCP)-functionalized tetraphenylsilane derivatives (SimCPx), including bis(3,5-di(9H-carbazol-9-yl)phenyl)diphenylsilane (SimCP2), tris(3,5-di(9H-carbazol-9-yl)phenyl)methylsilane (SimCP3-CH3), tris(3,5-di(9H-carbazol-9-yl)phenyl)phenylsilane (SimCP3-Ph), and tetrakis(3,5-di(9H-carbazol-9-yl)phenyl)silane (SimCP4), serving as bipolar blue hosts for bis[2-(4,6-difluorophenyl)pyridyl-N,C2']iridium(III) (FIrpic), have been synthesized by incorporating different ratios of mCP subunits into a central silicon atom. All of the SimCPx derivatives have wide bandgaps and high triplet energies because of the indirect linkage by silicon between each mCP subunit. The good solubility and high thermal and morphological stability of SimCPx are beneficial for forming amorphous and homogeneous films through solution processing. Density functional theory simulations manifest the better bipolar characteristics for SimCPx using three and four mCP units rather than the represented bipolar host SimCP2. As a result, SimCP4 presents the best electron-transporting ability for charge balance. Consequently, the lowest driving voltage of 4.8 eV, and the favorable maximum efficiencies of 14.2% for external quantum efficiency (28.4 cd A(-1), 13.5 lm W(-1)), are achieved by solution-processed, SimCP4-based blue phosphorescent organic light-emitting diodes as the highest performance among SimCPx, in which 32% improved device efficiencies compared to that of SimCP2 are obtained. It is inspiring to develop efficient bipolar hosts for blue phosphors by just incorporating monopolar carbazole into arylsilanes in two steps.
ACS Appl Mater Interfaces 2015 Aug 19
PMID:Multi-3,3'-Bicarbazole-Substituted Arylsilane Host Materials with Balanced Charge Transport for Highly Efficient Solution-Processed Blue Phosphorescent Organic Light-Emitting Diodes. 2625 13

The synthesis and characterization of a molecular tetrapod, SFBTD, featuring a tetraphenylsilane center and four identical conjugated arms, which structurally resembles breakwaters in common wave-reducing shore constructions, are reported. Cyclic voltammetry reveals that SFBTD has a medium band gap of ca. 2.0 eV and a low-lying HOMO energy level at ca. -5.2 eV. Absorption spectroscopy, X-ray diffraction, and differential scanning calorimetry experiments reveal a low degree of crystallinity in this compound and slow crystallization kinetics. Bulk heterojunction organic photovoltaics (OPVs) employing SFBTD and fullerene derivatives exhibit power conversion efficiencies (PCEs) up to 1.05% and open-circuit voltage (VOC) values as high as 1.02 V. To the best of our knowledge, this is the highest PCE obtained for OPVs employing molecular tetrapods as donor materials. These devices are relatively thermally stable due to the known ability of breakwater tetrapods to interlock, preventing dislodging and sliding. The lack of favorable phase separations and low hole mobilities of the blend films are the major factors limiting the device performance. Ternary blend devices by the addition of three low band gap poly(thienylene vinylene) (PTV) derivatives were fabricated and tested. We found that the added PTVs acted to be either the major hole conductor or a competing hole conduction channel depending on the HOMO level positions relative to that of SFBTD. Some of the ternary OPV devices out-performed the corresponding binary counterparts employing SFBTD or PTVs alone, suggesting cooperative effects in the ternary systems.
ACS Appl Mater Interfaces 2016 Aug 31
PMID:A Molecular Tetrapod for Organic Photovoltaics. 2751 35

Four wide bandgap host materials, namely, 9-(4-diphenyl(4-(pyridin-3-yl)phenyl)silyl-phenyl)-9H-carbazole (CSmP), 9-(4-diphenyl(4-(pyridin-2-yl)phenyl)silylphenyl)-9H-carbazole (CSoP), 9-(4-diphenyl(4-(pyridin-3-yl)phenyl)silylphenyl)-9H-3,9'-bicarbazole (DCSmP), and 9-(4-(diphenyl(4-(pyridin-2-yl)phenyl)silyl)phenyl)-9H-3,9'-bicarbazole (DCSoP), have developed by incorporation of pyridine with varied N atom orientation and carbazole/dimer carbazole units into the tetraphenylsilane skeleton for blue phosphorescent light-emitting diodes. These host materials all possess wide bandgap (3.54-3.64 eV) and high triplet energies (2.77-2.95 eV). As revealed by the absorption and emission spectra, theoretical calculations, and CV measurements, the N atom orientation exerts a strong influence on the LUMO energy level and electron-transportation behaviors without deterioring the photophysical properties. Among them, DCSmP with 3-pyridyl substituent manifests the best electron-transporting capability. The FIrpic-doped blue phosphorescent device using DCSmP as host material exhibits excellent electroluminescence performance with a maximum current efficiency of 40.1 cd A(-1) and a maximum external quantum efficiency of 20.0%. The current efficiency and external quantum efficiency are improved 3-fold, higher than those fabricated from DCSpP with 4-pyridyl as substituent, demonstrating an effective strategy for large improvement in device performance by a subtle change in molecular structure.
ACS Appl Mater Interfaces 2016 Sep 21
PMID:Adjusting Nitrogen Atom Orientations of Pyridine Ring in Tetraphenylsilane-Based Hosts for Highly Efficient Blue Phosphorescent Organic Light-Emitting Devices. 2757 8