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Elucidating the effects of guest-host energy level alignment on charge transport in phosphorescent OLEDs
摘要： The correct choice of guest and host molecules in the light-emitting layer is essential for developing high performance phosphorescent organic light emitting devices. However, the effects of the energy level alignment between the guest and the host are yet to be fully elucidated. In this Letter, we use kinetic Monte Carlo simulations to investigate guest-host systems in which the energy gap of the guest and host is fixed, and only the relative energies of the ionization potential/electron affinity are changed to elucidate their effect on charge transport. It was determined that the mobility balance in the blend was sensitive to the energy level alignment, allowing balanced active layer mobility to be achieved despite the hole and electron mobilities being different by around one order of magnitude. It was also found that the mobility of the faster carrier was more sensitive to the energy level alignment than that of the slower carrier due to reduced slower carrier thermalization under deep charge trapping on the guest.
关键词： guest-host energy level alignment,phosphorescent OLEDs,kinetic Monte Carlo simulations,charge transport
更新于2025-09-12 10:27:22
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Dual-Wavelength (UV and Blue) Controlled Photopolymerization Confinement for 3D-Printing: Modeling and Analysis of Measurements
摘要： The kinetics and modeling of dual-wavelength (UV and blue) controlled photopolymerization con?nement (PC) are presented and measured data are analyzed by analytic formulas and numerical data. The UV-light initiated inhibition e?ect is strongly monomer-dependent due to di?erent C=C bond rate constants and conversion e?cacies. Without the UV-light, for a given blue-light intensity, higher initiator concentration (C10) and rate constant (k’) lead to higher conversion, as also predicted by analytic formulas, in which the total conversion rate (RT) is an increasing function of C1 and k’R, which is proportional to k’[gB1C1]0.5. However, the coupling factor B1 plays a di?erent role that higher B1 leads to higher conversion only in the transient regime; whereas higher B1 leads to lower steady-state conversion. For a ?xed initiator concentration C10, higher inhibitor concentration (C20) leads to lower conversion due to a stronger inhibition e?ect. However, same conversion ? b2C20]. Conversion of blue-only are much higher than that of UV-only and UV-blue combined, in which high C20 results a strong reduction of blue-only-conversion, such that the UV-light serves as the turn-o? (trigger) mechanism for the purpose of spatial con?rmation within the overlap area of UV and blue light. For example, UV-light controlled methacrylate conversion of a glycidyl dimethacrylate resin is formulated with a tertiary amine co-initiator, and butyl nitrite. The system is subject to a continuous exposure of a blue light, but an on-o? exposure of a UV-light. Finally, we developed a theoretical new ?nding for the criterion of a good material/candidate governed by a double ratio of light-intensity and concentration, [I20C20]/[I10C10].
关键词： additive manufacturing,kinetic model,photopolymerization,dual-wavelength,spatial con?rmation,3D printing
更新于2025-09-12 10:27:22
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8.78% Efficient All‐Polymer Solar Cells Enabled by Polymer Acceptors Based on a B←N Embedded Electron‐Deficient Unit
摘要： Mono-cardboard waste digestion in batch tests associated with different impact factors was investigated. The maximum methane generation was 394 mL/gVSadd with the best F/M of 0.5 at mesophilic conditions. The highest methane content reached 75% in the dynamic water bath feeding with an average particle size of 1?3 mm. Hydrolysis and methanogenesis were significantly different between static and dynamic states, especially at particle size over 3 mm. The modified Gompertz model (R2 > 0.98) and the modified Aiba model (R2 > 0.88) were the most appropriate models for methane generation among the six kinds of models. At different TS, the variation of dissolved organic matters reflects the metabolic rate of the microbial community. The soluble microbial product-like and protein-like components half split by excitation?emission factors significantly negatively corresponded to biomethane production. Moreover, a rapid loss of matrix-parallel methanogenesis was observed with high organics concentration. A strong correlation between the F/M ratio and the CH4 generation ability was observed with an optimized F/M of 0.5. The maximum energy production was also investigated based on the optimized particle size of 2?5 mm and F/M of 0.5, in which long-term stability was maintained.
关键词： dissolved organic matter,kinetic models,methane production,EEM-PARAFAC,Mono-cardboard digestion
更新于2025-09-11 14:15:04
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Proton-Coupled Electron Transfer Kinetics for the Photoinduced Generation of a Cobalt(III)-Hydride Complex
摘要： Studying the formation of transition metal hydride complexes via proton-coupled electron transfer is important for developing next-generation molecular catalysts for hydrogen evolution. We report herein the study of stepwise photoinduced reduction and protonation of [CoIICp-(dppe)]+ (Cp = cyclopentadienyl, dppe = 1,2-bis-(diphenylphosphino)ethane) to form the corresponding hydride complex [HCoIIICp(dppe)]+. Reaction intermediates were optically tracked using transient absorption spectroscopy, and a combination of experimental fitting and kinetic simulations was used to determine apparent rate constants for electron transfer and proton transfer with a range of acid sources. A linear free energy relationship is observed between measured apparent proton transfer rate constants and acid strength, but marked differences from previously electrochemically determined protonation rate constants are found. These deviations, which stem from ground-state reactivity present in photochemical experiments, highlight the challenges in comparing mechanistic studies using different techniques.
关键词： kinetic simulations,transient absorption spectroscopy,transition metal hydride complexes,proton-coupled electron transfer,hydrogen evolution
更新于2025-09-11 14:15:04
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Development of an Optical Coupling with Ground-Side Absorption for Antenna-Coupled Kinetic Inductance Detectors
摘要： Antenna-coupled kinetic inductance detectors (KIDs) have recently shown great promise as microwave detection systems with a large number of channels. However, this technique, still has di?culties in eliminating the radiation loss of the resonator signals. To solve this problem, we propose a design in which the absorption area connected to an antenna is located on the ground-side of a coplanar waveguide. Thereby, radiation loss due to leakage from the resonator to the antenna can be considerably reduced. This simple design also enables the use of a contact aligner for fabrication. We have developed KIDs with this design, named as the ground-side absorption (GSA)-KIDs and demonstrated that they have higher quality factors than those of the existing KIDs, while maintaining a good total sensitivity.
关键词： superconducting detector,kinetic inductance detectors,optical coupling
更新于2025-09-11 14:15:04
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Carrier-envelope-phase–controlled molecular dissociation by ultrashort chirped laser pulses
摘要： We demonstrate and characterize that a carrier-envelope-offset-phase (CEP)–controlled ultrashort chirped ?eld is an ef?cient and robust mechanism to modify the dissociation dynamics of molecular hydrogen. Different dissociation pathways are collectively induced and their interference contributes to the kinetic-energy release spectra. Chirping is able to ef?ciently manipulate the interferences of different dissociation pathways. We demonstrate a linear relationship between chirp and CEP dependent dissociation as well as directional electron localization.
关键词： electron localization,molecular dissociation,carrier-envelope-phase,kinetic-energy release spectra,ultrashort chirped laser pulses
更新于2025-09-11 14:15:04
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Ultrafast polarization of an electron beam in an intense bichromatic laser field
摘要： Here, we demonstrate the radiative polarization of high-energy electron beams in collisions with ultrashort pulsed bichromatic laser fields. Employing a Boltzmann kinetic approach for the electron distribution allows us to simulate the beam polarization over a wide range of parameters and determine the optimum conditions for maximum radiative polarization. Those results are contrasted with a Monte Carlo algorithm where photon emission and associated spin effects are treated fully quantum mechanically using spin-dependent photon emission rates. The latter method includes realistic focusing laser fields, which allows us to simulate a near-term experimentally feasible scenario of an 8 GeV electron beam scattering from a 1 PW laser pulse and provide a measurement that would verify the ultrafast radiative polarization in high-intensity laser pulses that we predict. Aspects of spin-dependent radiation reaction are also discussed, with spin polarization leading to a measurable (5%) splitting of the energies of spin-up and spin-down electrons.
关键词： spin-dependent radiation reaction,Boltzmann kinetic approach,radiative polarization,Monte Carlo algorithm,electron beams,bichromatic laser fields
更新于2025-09-11 14:15:04
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Kinetic Monte Carlo Study of the Role of the Energetic Disorder on the Open-circuit Voltage in Polymer:Fullerene Solar Cells
摘要： One major factors limiting the e?ciency in organic solar cells (OSCs) is the low open-circuit voltage (Voc). Existing theoretical studies link the Voc with the charge transfer (CT) state and non-radiative recombination. However, also morphology and energetic disorder can have a strong impact on the Voc within realistic bulk-heterojunction OSCs. In this work, we present a kinetic Monte Carlo study on the role of the energetic disorder on the maximum Voc. We compute the quasi-Fermi level splitting for di?erent energetic disorder and analyze the impact of the energetic disorder at the donor-acceptor interface as well as correlations in the site energies on the Voc. Our results show that the interface strongly controls the maximum Voc. For a higher interface disorder, charge densities and non-geminate recombination increases, and the Voc is reduced. Furthermore, the correlated morphologies show an increase in the maximum Voc and a reduced impact of the energetic disorder.
关键词： Open-circuit Voltage,Kinetic Monte Carlo,Energy Conversion and Storage,Plasmonics and Optoelectronics,Polymer:Fullerene Solar Cells
更新于2025-09-11 14:15:04
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Complex Field Mapping of Large Direct Detector Focal Plane Arrays
摘要： Complex ?eld mapping is a powerful tool to characterize the optical performance of astronomical instruments, and has become the standard for characterizing heterodyne array cameras. Recently, an adaptation of the heterodyne beam mapping technique was demonstrated on a single pixel of a direct detector instrument. We present novel measurement apparatus and data acquisition techniques to e?ciently reconstruct the complex ?eld pattern of individual pixels across a direct detector focal plane array. These techniques are scalable to high pixel counts as the technology maturation and scienti?c requirements push to larger arrays. For this demonstration, we used an engineering model of the low frequency band of the Apex Microwave Kinetic Inductance Detector (AMKID) camera with a center frequency of ν = 350 GHz. Amplitude and phase radiation patterns were measured from all 880 pixels of the test array in two orthogonal polarizations. We also discuss an updated post-processing pipeline using the complex ?eld data to characterize the optical performance of the array. Using the measured complex ?eld pattern, we extract the co- and cross-polarization pattern, Gaussian beam parameters, and propagate the beam from the measurement plane to additional planes of interest across all pixels in the test array. Complex ?eld measurements of direct detectors allow more precise characterization of beam parameters when compared to thermal measurements, particularly for individualized ?tting in post-processing not reliant on the accuracy of the probe system alignment. These techniques enable high-precision characterization of individualized beam parameters as well as the overall optical system to very large format arrays with modest computational processing power. These results demonstrate the diagnostic power of the presented measurement and analysis techniques.
关键词： optical characterization,kinetic inductance detector,near to far ?eld transformation,complex ?eld mapping,Gaussian beam analysis
更新于2025-09-11 14:15:04
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Terahertz Transition-Edge Sensor with Kinetic-Inductance Amplifier at 4.2 K
摘要： Different terrestrial terahertz applications would benefit from large-format arrays, operating in compact and inexpensive cryocoolers at liquid helium temperature with sensitivity, limited only by the 300-K background radiation. A voltage-biased Transition-Edge Sensor (TES) as a THz detector can have sufficient sensitivity and has a number of advantages important for real applications: linearity of response, high dynamic range and a simple calibration. However it requires a low-noise current readout. Usually, a current amplifier based on Superconducting Quantum-Interference Device (SQUID) is used for readout, but the scalability of this approach is limited due to complexity of the operation and fabrication. Recently, it has been shown that instead of SQUID it is possible to use a current sensor, which is based on the nonlinearity of the kinetic inductance of a current-carrying superconducting stripe. Embedding the stripe into a microwave high-Q superconducting resonator allows for reaching sufficient current sensitivity. More important, it is possible with the resonator approach to scale up to large arrays using Frequency-Division Multiplexing (FDM) in GHz range. Here, we demonstrate the operation of a voltage-biased TES with a microwave kinetic-inductance current amplifier at 4.2 K. We measured the expected intrinsic Noise-Equivalent Power NEP ~ 5×10-14 W/Hz1/2 and confirmed that a sufficient sensitivity of the readout can be reached in conjunction with a real TES operation. The construction of an array with the improved sensitivity ~ 10-15 W/Hz1/2 at 4.2 K could be realized using a combination of the new current amplifier and already existing TES detectors with improved thermal isolation.
关键词： Transition-Edge Sensor,Superconducting nanowire,High-Q resonator,Nonlinear kinetic inductance,Terahertz arrays
更新于2025-09-11 14:15:04