- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Riboflavin-induced Type 1 photo-oxidation of tryptophan using a high intensity 365 nm light emitting diode
摘要： The mechanism of photo-oxidation of tryptophan (Trp) sensitized by riboflavin (RF) was examined employing high concentrations of Trp and RF, with a high intensity 365 nm light emitting diode (LED) source under N2, 20% and 100% O2 atmospheres. Dimerization of Trp was a major pathway under the N2 atmosphere, though this occurred with a low yield (DφTrp = 5.9 x 10-3), probably as a result of extensive back electron transfer reactions between RF●- and Trp(H)●+. The presence of O2 decreased the extent of this back electron transfer reaction, and the extent of Trp dimerization. This difference is attributed to the formation of O2●- (generated via electron transfer from RF●- to O2) which reacts rapidly with Trp● leading to extensive consumption of the parent amino acid and formation of peroxides and multiple other oxygenated products (N-formylkynurenine, alcohols, diols) of Trp, as detected by LC-MS. Thus, it appears that the first step of the Type 1 mechanism of Trp photo-oxidation, induced by this high intensity 365 nm light source, is an electron transfer reaction between the amino acid and 3RF, with the presence of O2 modulating the subsequent reactions and the products formed, as a result of O2●- formation. These data have potential biological significance as LED systems and RF-based treatments have been proposed for the treatment of pathological myopia and keratitis.
关键词： type 1/type 2 mechanisms,dimers,LED,N-formylkynurenine,trimers,riboflavin,photo-oxidation,electron transfer,photobleaching,tryptophan,triplet excited state
更新于2025-09-23 15:21:21
-
Nanophotonic energy storage in upconversion nanoparticles
摘要： In nanophotonic energy storage, an energy conversion model is established for intrinsic nanophotonic energy storage (NPES) effects. Here we realize that the charge inhomogeneous distribution on the surface of upconversion nanoparticles (UCNPs) would persistently exist as well as the formation and migration of surface defects states despite of the compound component ratio, even following the stringent stoichiometric ratio. Our preliminary efforts on NPES effect has recognized from the recent published work [Nature 561, 88 (2018)], which the surface quantum confinement arose because of a recently found surface vacancy induced Coulomb states (SVIC) states. Further in-depth excavation on surface charge density distributions and defect orbitals of surface localized electronics and holes have affirmatively repeated the Guerra’s theory [Nature 554, 346 (2018)] and reflected the existence of surface defect states in both stoichiometric and non-stoichiometric compounds. Therefore, beyond the experimental trail-based multi-doping chemical modifications, we proposed the surface electronic process for efficient NPES effect can be modulated by an intrinsic level-matching induced surface resonant quantum tunneling (LM-SRQT) in this work. The UCNP size-effect can be confirmed that simply might be not an influencing factor of dominating NPES effect while the surface degree of non-crystallizations indeed matters.
关键词： level-matching induced surface resonant quantum tunneling (LM-SRQT),surface vacancy induced Coulomb states (SVIC) states,nano energy,nanophotonic energy storage (NPES),electron-transfer surface mechanism
更新于2025-09-23 15:21:21
-
[IEEE 2018 9th International Conference on Ultrawideband and Ultrashort Impulse Signals (UWBUSIS) - Odessa, Ukraine (2018.9.4-2018.9.7)] 2018 9th International Conference on Ultrawideband and Ultrashort Impulse Signals (UWBUSIS) - Wide-Band Gunn Diodes Based on Graded-Gap InGaP/ InP As
摘要： The paper presents the results of numerical experiments on the oscillation generation using the n+-n-n+ transfer electron device based on InGaP/InPAs graded-gap semiconductor compounds at different Ga and As distributions. The active region of the diode is 2.5 μm with an ionized impurity concentration of 1016 cm–3. It is paper shown that the output power and the efficiency of Gunn generators increase several times when the InGaP/InPAs graded-gap semiconductors are used. The reasons for this increase are considered. The highest power of 11.3 kW/cm2 with efficiency of 10.2% at frequency of 40 GHz belong to In0.4Ga0.6P/InP0.4As0.6 diode.
关键词： graded-gap semiconductor,indium gallium phosphide,intervalley electron transfer,indium phosphide with arsenide,Gunn diode,transfer electron device,output power
更新于2025-09-23 15:21:01
-
Luminescence and reactivity of a charge-transfer excited iron complex with nanosecond lifetime
摘要： Iron’s abundance and rich coordination chemistry are potentially appealing features for photochemical applications. However, the photoexcitable charge-transfer (CT) states of most Fe complexes are limited by picosecond or sub-picosecond deactivation through low-lying metal centered (MC) states, resulting in inefficient electron transfer reactivity and complete lack of photoluminescence. Here we show that octahedral coordination of Fe(III) by two mono-anionic facial tris-carbene ligands can suppress such deactivation dramatically. The resulting complex [Fe(phtmeimb)2]+, where phtmeimb is [phenyl(tris(3-methylimidazol-1-ylidene))borate]-, exhibits strong, visible, room temperature photoluminescence with a 2.0 ns lifetime and 2% quantum yield via spin-allowed transition from a ligand-to-metal charge-transfer (2LMCT) state to the ground state (2GS). Reductive and oxidative electron transfer reactions were observed for the 2LMCT state of [Fe(phtmeimb)2]+ in bimolecular quenching studies with methylviologen and diphenylamine.
关键词： charge-transfer,iron complex,electron transfer,photoluminescence,N-heterocyclic carbene
更新于2025-09-23 15:21:01
-
Multicolor Luminescent Patterning via Photoregulation of Electron and Energy Transfer Processes in Quantum Dots
摘要： Ability to create high-contrast multicolor luminescent patterns is essential to realize the full potential of quantum dots (QDs) in display technologies. The idea of using a non-emissive state is adopted in the present work to enhance the color-contrast of QD based photopatterns. This is achieved at a multicolor level by the photoregulation of electron and energy transfer processes in a single QD nanohybrid film, comprising of one QD donor and two dye acceptors. The dominance of photoinduced electron transfer over energy transfer process generates a non-luminescent QD nanohybrid film, which provides the black-background for multicolor patterning. The superior photostability of QDs over dyes is used for the photoregulation of electron and energy transfer processes. Selective photodegradation of electron acceptor dye triggered the onset of energy transfer process, thereby imparting a luminescent color to QD nanohybrid film. Further, a controlled photoregulation of energy transfer process paved the way for multicolor patterning.
关键词： Energy and electron transfer,Thin films,Quantum dots,Multicolor photopatterning,Light harvesting
更新于2025-09-23 15:21:01
-
Organic Solar Cells Efficiency Enhanced by Perylene Mono-Imide Phosphorus Salt Cathode Interfacial Layer
摘要： The composite high-performance electrode is very important for excellent photoelectric device. Interfacial modification is the dominating method to optimize electrode properties. Two easy synthesized perylene-monoimide (PMI) derived organic phosphonium bromide salts were found interestingly valuable when they were applied as cathode interlayers (CIL) in bulk heterojunction (BHJ) organic solar cells (OSCs). Using the PBDB-T:ITIC blend as bulk-hererojunction active layer in inverted device structure, the power conversion efficiency (PCE) was greatly improvement from 9.49% of the referenced device which is without phosphonium CIL to PCE 10.42% with PMI-triphenyl-phosphonium bromide (PMI-TPP) and PCE 9.87% with PMI- trimethoxylphenylphosphonium bromide (PMI-TMOPP) as CIL. Moreover, the two organic phosphonium bromide salts were also investigated by traditional device structure, the PCE was of 4.21% for bare aluminium cathode referenced device contrasted to a moderate increased PCE of 5.18% with PMI-TPP CIL or PCE of 5.05% with PMI-TMOPP CIL. Therefore, organic phosphonium bromide salt PMI-TPP is a promising candidate of CIL material in OSCs.
关键词： cathode interlayer,organophosphorus,energy conversion,electron transfer,solar cell
更新于2025-09-23 15:21:01
-
Charge separation and electron transfer routes modulated with Co-Mo-P over g-C3N4 photocatalyst
摘要： In this case, a novel photocatalyst with visible light harvesting, spatial charge separation and effective electron transfer route is reported, which assemble Co-Mo-P nanoparticle on the surface of g-C3N4. The composite photocatalyst shows high H2 evolution with a yield of 646.4 μmol in 5 h, which is 66.7 times than over the pristine g-C3N4. The AQE measured was reached 5.25% at the wavelength of 475 nm after 1 h. The inner reason was comprehensively studied and understood by means of FESEM, HRTEM, XRD, XPS, UV–vis DRS and BET. Especially the investigation of their photoelectrochemical properties with photocurrent, voltammetric scanning, fluorescence spectra, etc. The characterization results show that CoMoP forms a large number of active sites on the surface of g-C3N4, which improves efficiency of the charge transfer and then accelerates the rate of HER. At the same time, the mechanism of H2 production of photocatalyst in the eosin Y sensitization system was proposed.
关键词： Hydrogen production,Electron transfer,Charge separation,Photocatalysis
更新于2025-09-23 15:21:01
-
Biaryl Crossa??Coupling Enabled by Photoa??Induced Electron Transfer
摘要： We report a protocol for aryl cross-coupling of electron-deficient aryl halides with electron-rich (hetero)arenes that is driven solely by violet light. This process takes advantage of formation of photo-excited state of electron-deficient aryl halides, that are reduced by electron-rich (hetero)arenes to form a pair of aryl anion and cation radicals. The resulting aryl anion radicals of aryl halides undergo mesolysis of the carbon-halogen bond to generate aryl radicals, that are coupled most likely with aryl cation radicals to afford functionalized biaryls.
关键词： Single-electron-transfer,Visible light,Anion radicals,Aryl radicals,Cross-coupling
更新于2025-09-23 15:21:01
-
POM-based dyes featured rigidified bithiophene ?? linkers: Potential high-efficient dyes for dye-sensitized solar cells
摘要： A series of POM-based dyes with triphenylamine electron donor group, cyanoacrylic acid electron acceptor group and different π linkers of thiophene derivatives are systematically investigated to analyze the influence of rigidified bithiophene with fastening atoms (C and N) on the performance of dye-sensitized solar cells (DSSCs) based on density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations. The interfacial electron transfer (IET) processes are evaluated, which is less investigated previously. We can see that the electron in dyes 2, 4 and 5 are almost completely injected after 100 fs, thus leading to the fast IET. Dye 2 not only has lower interaction energy for most stable dimer configuration than dye 1, but also has larger short-circuit photocurrent density JSC and open-circuit photovoltage VOC, resulting from the insertion of POM group. Compared with dye 3 containing 2,2'-bithiophene π linker, its two counterparts (dyes 4 and 5) with rigidified bithiophene π linkers tend to accelerate IET process as well as retard the electron recombination, thus improve the performance of DSSCs. In particular, dye 4 with rigidified bithiophene π linker fastening by C atom would obtain the larger JSC and VOC than that of dye 5 with N atom rigidified bithiophene π linker.
关键词： rigidified bithiophene,POM-based dyes,interfacial electron transfer,dye-sensitized solar cells,density functional theory
更新于2025-09-23 15:21:01
-
Assessing the Performance of Cobalt Phthalocyanine Nanoflakes as Molecular Catalysts for Li-Promoted Oxalate Formation in Li–CO <sub/>2</sub> –Oxalate Batteries
摘要： Removal of O2 molecules from the cathode environment in the Li-based battery has led to introduction of the Li?CO2 battery as the novel and promising source of energy storage. In spite of CO2 capture through the reversible reaction between Li atoms and CO2 molecules at the cathode, the performance of the Li?CO2 battery is hampered by formation of the Li2CO3 insulating product in the discharge process and its di?cult decomposition in the charging process. Hereby, we explore the possible improvement of the performance of the Li?CO2 battery through replacement of Li2CO3 by Li2C2O4 as the discharge product. This is achieved by systematic addition of Li and CO2 to a cobalt phthalocyanine (CoPc) nano?ake employed as the molecular catalyst in the cathode of the Li?CO2 battery by means of computational density functional theory-based methods. The present results predict high adsorption energy of the CO2 molecules (?2.16 eV), low Li-intercalation voltage (1.45 V), reveal the important and constructive in?uence of the electrolyte (dimethyl sulfoxide) on the adsorption and decomposition energies and Li-intercalation voltage, and suggest a through-space electron transfer mechanism for the formation of the Li2C2O4 product on the CoPc nano?ake. Moreover, the high electron a?nity of the CoPc nano?ake along with the suitable thermodynamics and kinetics of electron transfer from the CoPc nano?ake to the CO2 molecules during the formation of the Li2C2O4 product con?rm the potential abilities of the CoPc nano?ake to be used in the Li?CO2 battery. Therefore, present results provide a sound assessment of the capability of the CoPc nano?ake as a cathode material in the Li?CO2 battery and show that this provides a possible and e?ective solution to improve the performance of the Li?CO2 battery and to introduce new Li?CO2?oxalate batteries.
关键词： Li?CO2 battery,cobalt phthalocyanine,electron transfer mechanism,density functional theory,molecular catalyst
更新于2025-09-23 15:21:01