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Unraveling Correlations between Molecular Properties and Device Parameters of Organic Solar Cells Using Machine Learning
摘要： Understanding the relationships between molecular properties and device parameters is highly desired not only to improve the overall performance of an organic solar cell but also to fulfill the requirements of a device for a particular application such as solar to fuel energy conversion (high VOC) and solar-window applications (high JSC). In this work, a series of machine learning models are built for three important device characteristics (VOC, JSC, and FF) using 13 crucial molecular properties as descriptors, with an impressive predictive performance (r=0.7). These models may play a vital role in designing promising organic materials for a specific photovoltaic application with high VOC/JSC. The importance of descriptors for each device parameter is unraveled, which may assist in tuning them and improve understanding of the energy conversion process.
关键词： virtual screening,organic photovoltaics,machine learning,conjugated molecules,Organic solar cells
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Fluorescence-Based Sensors and Preconcentration Techniques for Buried Explosives Detection
摘要： Trace detection of explosives is an important challenge in both humanitarian landmine clearance and in homeland security scenarios. The ability to detect the presence of explosives across an area of interest would be of particular use in technical surveys of suspected minefields. In this paper we present the development and application of fluorescence-based trace-explosives sensors based on organic semiconductor thin films. We show that these can be used to detect nano-gram level quantities of nitroaromatic (TNT-like) molecules, and combine them for the first time with a novel preconcentration approach to detect buried explosives. Initial field trials on a test minefield will also be presented, in which the sensors are used to detect trace explosives collected by colonies of foraging honeybees.
关键词： fluorescence-based sensors,nitroaromatic molecules,buried explosives detection,organic semiconductor thin films,preconcentration techniques
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Planar Optical Antennas as Efficient Single-Photon Sources for Free-Space and Fiber-Based Operation in Quantum Optics and Metrology
摘要： Practical implementations of quantum technologies, ranging from optical quantum computing to metrological measurements, suffer from the lack of high-rate, on-demand sources of indistinguishable single photons. We will discuss a simple and versatile planar optical antenna, showing both theoretical and experimental evidence of low-loss (< 20%) beaming of the radiation from a single quantum emitter into a narrow cone of solid angles in free space, which allows in principle up to 50% coupling into a single-mode fiber. In particular, we will first present an experimental implementation of the design operated at room temperature, exploiting Dibenzoterrylene molecules (DBT) hosted in a crystalline anthracene matrix (Ac) [1]. The DBT:Ac system is particularly suitable for this task, due to its outstanding photo-physical properties (i.e. long-term photostability both at room and cryogenic temperature, lifetime-limited emission at cryogenic temperatures, 780 nm operating wavelength) demonstrated in 50 nm-thick crystals [2] and recently also in nanocrystals [3]. Moreover, single photons from DBT molecules and similar [4] result very appealing concerning quantum communication and computation protocols which involve quantum memories, due to the unmatched stability and narrowness of their spectrum (below 100 MHz). Then we will report on our theoretical study to determine the ultimate performances attainable with such design in case of operation in cryogenic environment, exploring materials and fine tuning of geometrical parameters. We will finally discuss our recent results about a single-mirror antenna operating at cryogenic temperature. We demonstrate a photon flux in the Fourier-limited line higher than 1MHz at detectors, and coupling of fluorescence into single-mode fibers up to 46%. These results open to the deploiment of our system both in quantum optics experiments requiring deterministic single-photon sources and in metrology, in particular for a new operative definition of the candela, as recently proposed in the EMPIR project 'SIQUST' [5].
关键词： Quantum Optics,Single-Photon Sources,Dibenzoterrylene molecules,Metrology,Planar Optical Antennas,Crystalline anthracene matrix
更新于2025-09-12 10:27:22
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F?rster Resonance Energy Transfer between Colloidal CuInS2/ZnS Quantum Dots and Dark Quenchers
摘要： F?rster resonance energy transfer (FRET) using colloidal semiconductor quantum dots (QDs) and dyes is of importance in a wide range of biological and biophysical studies. Here, we report a study on FRET between CuInS2/ZnS QDs and dark quencher dye molecules (IRDye QC-1). Oleate-capped QDs with photoluminescence quantum yields (PLQYs) of 55±4% are transferred into water by using two types of multifunctional polymer ligands combining imidazole groups and specific moieties with amine or methoxy groups as the terminal sites. The resulting water-dispersible QDs show PLQYs as high as 44±4% and exhibit long-term colloidal stability (at least 10 months at 4 °C in the dark) with a hydrodynamic diameter of less than 20 nm. A side-by-side comparison experiment was performed using the amine or methoxy-functionalized QDs for coupling to dark quencher dye molecules. The amine-functionalized QDs bind to the dye molecules via covalent bonds while methoxy-functionalized ones bind only weakly and non-specifically. The progressive quenching of the QD emission and shortening of its photoluminescence decay time upon increasing the number of conjugated dye molecules demonstrate that the QD acts as the energy donor and the dark quencher dye as the energy acceptor in a donor-acceptor FRET pair. The FRET dynamics of the QD-dye conjugates are simulated using two different models based on the possible origin of the multiexponential PL decay of the QDs (i.e., variations in nonradiative or radiative decay rates). The model based on the radiative decay rates provides a better fit of our experimental data and estimates a donor–acceptor distance (6.5 nm) that matches well the hydrodynamic radius of the amine-functionalized QDs.
关键词： dark quencher dye molecules,energy acceptor,multifunctional polymer ligands,CuInS2/ZnS,F?rster resonance energy transfer,colloidal semiconductor quantum dots,energy donor,photoluminescence quantum yields
更新于2025-09-12 10:27:22
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Light drag via electron tunneling and incoherent pumping in semiconductor three-level InAs/GaAs double quantum dot molecules
摘要： We theoretically investigate the lateral and rotary light-drag in semiconductor three-level InAs/GaAs double quantum dot molecules. No coherent laser ?elds are used and the coherence is created by interdot electron tunneling. The e?ect of interdot electron tunneling on lateral and rotary light-drag is discussed. Moreover, it is shown that applying an incoherent pumping ?eld to the probe transition changes the subluminal to superluminal condition. It is observed that the light polarization state drags opposite and along with the medium motion in superluminal and subluminal propagating regions, respectively.
关键词： quantum dot molecules,incoherent pumping,electron tunneling,semiconductor,light-drag
更新于2025-09-12 10:27:22
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Cruciform Molecules Bearing Bis(phenylsulfonyl)benzene Moieties for High‐Efficiency Solution Processable OLEDs: When Thermally Activated Delayed Fluorescence Meets Mechanochromic Luminescence
摘要： Four crucifix-shaped molecules, named TPA-BPSB, DMAc-BPSB, MTPA-BPSB and MDMAc-BPSB, bearing the same acceptor fragment of bis(phenylsulfonyl)benzene (BPSB) and different donor segments (TPA and MTPA are the diphenylamine derivatives while DMAc and MDMAc are the 9,9-dimethylacridine derivatives) are synthesized and characterized by NMR, mass spectra, and single crystal X-ray crystallography. The molecular structure–property relationship of these crucifix-shaped molecules is systematically explored. All compounds display thermally activated delayed fluorescence (TADF) in the region of 500–550 nm. In addition, charming mechanochromic luminescence properties are observed for all these TADF molecules under external stimuli, such as grinding and exposure to CH2Cl2 vapor. Four TADF molecules are used as the emitters in organic light-emitting diodes (OLEDs) fabricated via solution process. MTPA-BPSB-based device presents a best performance with a highest external quantum efficiency of ≈21%, which is among the highest efficiencies for reported BPSB-based solution-processable OLEDs so far. This research has an important significance in designing high-efficiency multifunctional TADF molecules.
关键词： bis(phenylsulfonyl)benzene,thermally activated delayed fluorescence,mechanochromic luminescence,crucifix-shaped molecules,solution processable OLEDs
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Photoelectron Circular Dichroism at the Few-Cycle Limit in the Tunnel Ionization Regime
摘要： Photoelectron circular dichroism (PECD) is a process that leads to a forward-backward asymmetry (with respect to the laser propagation direction) in photoelectron distributions created upon interaction of a circularly or elliptically polarized laser with a chiral molecule. The PECD effect has been shown in a broad range of ionization mechanisms from direct photoionization through multi-photon regime, above-threshold ionization to the tunnel ionization [1]. The fact that the effects of chirality can be observed in the tunnel ionization regime opens up the possibility to connect this fundamental effect to strong-field science with prospects for studying and driving sub-laser-cycle and attosecond phenomena connected to PECD [2]. However, a thorough understanding of PECD in the tunneling regime is of yet missing. In this study the effect of trajectory related parameters like electron energy or CEP on the PECD is investigated in order to determine the role of the scattering on the chiral potential.
关键词： few-cycle laser pulses,tunnel ionization,Photoelectron circular dichroism,chiral molecules
更新于2025-09-12 10:27:22
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3D nanoporous plasmonic chips for extremely sensitive NO <sub/>2</sub> detection
摘要： The detection of toxic gas molecules using the surface-enhanced Raman spectroscopy (SERS) technique is very challenging due to the low affinity of gas molecules. Here, we report extremely sensitive SERS-based NO2 gas sensors based on 3D nanoporous Au nanostructures with a high affinity for NO2 gas molecules and high density of hotspots.
关键词： SERS,toxic gas molecules,3D nanoporous plasmonic chips,surface-enhanced Raman spectroscopy,NO2 detection
更新于2025-09-12 10:27:22
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A novel candle light-style OLED with a record low colour temperature
摘要： Candle light-style OLEDs based on new D–A–π–A type molecules incorporated into Alq3 matrix were developed. A record low colour temperature of 1722 K OLED radiation was achieved, which is by 80 K lower than that of the best devices reported previously.
关键词： colour temperature,Alq3 matrix,D–A–π–A type molecules,candle light-style,OLED
更新于2025-09-12 10:27:22
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DNA Enabled Chiral Gold Nanoparticle - Chromophore Hybrid Structure with Resonant Plasmon – Exciton Coupling Gives Unusual and Strong Circular Dichroism
摘要： Circular dichroism (CD) from hybrid complexes of plasmonic nanostructures and chiral molecules has recently attracted significant interest. However, the hierarchical chiral self-assembly of molecules on surfaces of metal nanostructures has remained challenging. As a result, a deep understanding of plasmon-exciton coupling between surface plasmons and chiral collective molecular excitations has not been achieved. In particular, the critical impact of resonant plasmon-exciton coupling within the hybrid is unclear. Here, we employed DNA-templated strategies to control the chiral self-assembly of achiral chromophores with rationally tuned exciton transitions on gold nanosphere (AuNP) or gold nanorod (AuNR) surfaces. Unlike many previous chiral plasmonic hybrids utilizing chiral biomolecules with CD signals in the UV range, we designed structure with the chiral excitonic resonances at visible wavelengths. The constructed hybrid complexes displayed strong chiroptical activity that depends on the spectral overlap between the chiral collective molecular excitations and the plasmon resonances. We find that when spectral overlap is optimized, the molecular CD signal originating from the chiral self-assemblies of chromophores was strongly enhanced (maximum enhancement of nearly an order of magnitude) and a plasmonic CD signal was induced. Surprisingly, the sign of the molecular CD was reversed despite different self-assembly mechanisms of the Au nanoparticle-chromophore hybrids. Our results provide new insight into plasmonic CD enhancements and will inspire further studies on chiral light-matter interactions in strongly coupled plasmonic-excitonic systems.
关键词： DNA-templated strategies,gold nanorod,chiral molecules,chiroptical activity,gold nanosphere,Circular dichroism,plasmonic nanostructures
更新于2025-09-12 10:27:22