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- 摘要
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- 实验方案
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Power Electronicsa??Enabled Autonomous Power Systems (Next Generation Smart Grids) || Synchronverter Based Transformerless Photovoltaic Systems
摘要： New spectrum bands together with flexible spectrum management are treated as one of the key technical enablers the so-called key-performance indicators for achievement of defined for 5G wireless networks. In this paper, we deal with the small-scale spectrum aggregation and sharing, where a set of even very narrow and disjoint frequency bands closely located on the frequency axis can be utilized simultaneously. We first discuss how such a scheme can be applied to various multicarrier systems, focusing on the non-contiguous orthogonal frequency division multiplexing and non-contiguous filter-bank multicarrier technique. We propose an interference model that takes into account the limitations of both transmitter and receiver frequency selectivity, and apply it to our 5G link-optimization framework, what differentiates our work from other standard approaches to link adaptation. We present the results of hardware experiments to validate assumed theoretical interference models. Finally, we solve the optimization problem subject to the constraints of maximum interference induced to the protected legacy systems (GSM and UMTS). Results confirm that small-scale spectrum aggregation can provide high throughput even when the 5G system operates in a dense heterogeneous network.
关键词： spectrum aggregation,co-channel and adjacent-channel interference,Spectrum sharing,non-contiguous multicarrier systems
更新于2025-09-23 15:19:57
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Computational DFT calculations, photovoltaic properties and synthesis of (2R, 3S)-2, 3, 4-trihydroxybutoxy substituted phthalocyanines
摘要： In this study, 4-((2R, 3S)-2, 3, 4-trihydroxybutoxy) phthalonitrile was synthesized and characterized as starting material. This new starting material reacts with cobalt and copper metal salts to obtain metallophthalocyanine complexes. The electronic absorption of cobalt and copper phthalocyanine compounds in different concentrations of THF was investigated. In addition, the solubility and absorption of the compounds in different solvents were investigated. Density functional theory was also performed to support the relevant experimental results of the synthesized copper and cobalt center atomic compound. The photovoltaic performance of compounds was measured as current density–voltage (J–V).
关键词： DFT calculations,aggregation,photovoltaic,synthesis,Phthalocyanine
更新于2025-09-23 15:19:57
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Light-Triggered Dual-Modality Drug Release of Self-Assembled Prodrug-Nanoparticles for Synergistic Photodynamic and Hypoxia-Activated Therapy
摘要： Photodynamic therapy (PDT) leads to tumor hypoxia which could be utilized for the activation of hypoxia-activated prodrugs (HAPs). However, conventional photosensitizer-loaded nanoformulations suffer from aggregation-caused quenching (ACQ) effect, which limits the efficiency of PDT and synergistic therapy. Herein, prodrug-nanoparticles (NPs) are prepared by the self-assembly of heterodimeric prodrugs composed of pyropheophorbide a (PPa), hypoxia-activated prodrug PR104A, and a thioether or thioketal linkage. In addition, a novel dual-modality drug release pattern is proposed on the basis of the structural states of prodrug-NPs. Under light irradiation, PR104A is released via photoinduced electron transfer (PET) due to the aggregating state of prodrugs. With the disassembly of prodrug-NPs, ACQ effect relieves, PPa produces singlet oxygen which further promotes the reactive oxygen species (ROS)-sensitive release of PR104A. Such prodrug-NPs turn the disadvantage of the ACQ effect to facilitate drug release, demonstrating high-efficiency synergy in combination with PDT and hypoxia-activated therapy.
关键词： aggregation-caused quenching,Photodynamic therapy,drug release,photoinduced electron transfer,hypoxia-activated prodrugs,reactive oxygen species
更新于2025-09-23 15:19:57
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Thioalkyl-Functionalized Bithiophene (SBT)-Based Organic Sensitizers for High-Performance Dye-Sensitized Solar Cells
摘要： A series of 3,3′-dithioalkyl-2,2′-bithiophene (SBT)-based organic chromophores were designed and developed for the use in dye-sensitized solar cells (DSSCs). By appropriate structural modification of the SBT π-linkers with different alkyl chains and conjugated thiophene units, chromophore aggregation and interfacial charge recombination could be suppressed to a remarkable degree. Single-crystal and optical/electrochemical data clearly show that the SBT core is nearly planar with the torsional angle <1°, likely via S(alkyl)···S(thiophene) intramolecular locks. Therefore, this highly π-conjugated unit should enhance panchromatic light-harvesting and prove to be an excellent core for organic dye. For comparison, the 3,3′-dialkyl-2,2′-bithiophene (BT)-based dye was also prepared. Under 1 sun (100 mW cm?2) illumination, an optimized SBT-6 dye-sensitized cell indicates a short-circuit current density (JSC) of 17.21 mA cm?2, an open-circuit voltage (VOC) of 0.78 V, and a fill factor (FF) of 0.71, corresponding to a power conversion efficiency (η) of 9.47%, which is nearly two times higher than that of alkylated bithiophene (BT)-based chromophores. Finally, the proposed sensitizer SBT-6 exhibited an excellent η of 23.57% under the T5 fluorescent illumination of 6000 lux. To the best of our knowledge, this is the highest power conversion efficiencies (PCE) value reported to date among the studied thiophene or bithiophene-based chromophores.
关键词： aggregation,T5 fluorescent illumination,panchromatic light-harvesting,3, 3′-dithioalkyl-2, 2′-bithiophene,S(alkyl)···S(thiophene) intramolecular locks
更新于2025-09-23 15:19:57
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Spatiotemporal dynamics of aggregation-induced emission enhancement controlled by optical manipulation
摘要： We present spatiotemporal control of aggregation-induced emission enhancement (AIEE) of a protonated tetraphenylethene derivative by optical manipulation. A single submicrometer-sized aggregate is initially confined by laser irradiation when its fluorescence is hardly detectable. The continuous irradiation of the formed aggregate leads to sudden and rapid growth, resulting in bright yellow fluorescence emission. The fluorescence intensity at the peak wavelength of 540 nm is tremendously enhanced with growth, meaning that AIEE is activated by optical manipulation. Amazingly, the switching on/off of the activation of AIEE is arbitrarily controlled by alternating the laser power. This result means that local concentration, which increases the optical manipulation tool overcomes the electrostatic repulsion between the protonated molecules, namely, optical manipulation changes the aggregate structure. The dynamics and mechanism in AIEE controlled by optical manipulation will be discussed from the viewpoint of molecular conformation and association depending on the laser power.
关键词： Aggregation-induced emission enhancement,Fluorescence microspectroscopy,tertiary ammonium-appended tetraphenylethene,Spatiotemporal control,Optical manipulation
更新于2025-09-23 15:19:57
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5, 10, 15, 20-tetrakis-(4-methoxyphenyl) porphyrin film/K+ ion-exchanged optical waveguide gas sensor
摘要： Optical waveguide (OWG) sensors are widely used in gas detection, and sensitive materials are the key factors affecting sensor performance. Herein, we report on a 5,10,15,20-tetrakis-(4-methoxyphenyl) porphyrin (TMP) deposited optical wave guide (OWG) sensor. The porphyrin solutions with different acidity were deposited on a K+-ion exchanged glass OWG surface by spin coating, to fabricate porphyrin film-coated OWG gas sensing devices. The effects of pH values of the porphyrin solution used to prepare the sensitive film on the sensing properties of these devices were investigated. The gas sensitive performances of these devices in response to analytes were compared. Among them, the sensing devices fabricated using original and acidic solutions of porphyrin exhibited significant responses to sulfide gases and ethanediamine, respectively. The sensing device prepared using an acidic solution has a good response to ethanediamine gas (response and recovery times of the sensor for 1 ppm of EDA (ΔI = 48) are 13 and 38 s, respectively). The RSD of the output light intensity is ± 2.84, the signal to noise ratio (S/N) is 5.6. The device prepared using the original solution has an excellent response to sulfide gases (H2S, SO2), and can detect low concentration levels (ppm) of sulfide gases. These sensing devices thus have the potential to be used in food quality testing and environmental monitoring.
关键词： Aggregation,Ethanediamine,5,10,15,20-tetrakis-(4-methoxyphenyl) porphyrin,Optical waveguide gas sensor,Sulfide gases
更新于2025-09-23 15:19:57
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Ice Confinement-Induced Solubilization and Aggregation of Cyanonaphthol Revealed by Fluorescence Spectroscopy and Lifetime Measurements
摘要： When an aqueous salt solution freezes, a freeze concentrated solution (FCS) separates from ice. The properties of the FCS may differ from those of a supercooled bulk solution of the same ionic strength at the same temperature. The fluorescence and lifetime characteristics of 6-cyano-2-naphthol (6CN) were studied in frozen NaCl solutions to provide an insight into the solution properties of the FCS. While the photoacidity of 6CN in an FCS is similar to that in solution, several anomalous behaviors are observed. Fluorescence spectra indicate that the solubility of 6CN is significantly enhanced in the FCS (50 mM or higher) compared to that in bulk NaCl solution, where the solubility limit is 250 μM. The high solubility induces aggregation of 6CN in the FCS, which is not detected in bulk solutions. This trend becomes marked as the initial NaCl concentration decreases, that is, the FCS is confined in a small space. The fluorescence lifetimes of 6CN in the FCS support the spectroscopy results. In addition to the species identified by fluorescence spectroscopy, excimers are assigned from lifetime measurements in the FCS. The excimer formation is also a result of the enhanced solubility of 6CN in the FCS.
关键词： solubility enhancement,aggregation,lifetime measurements,excimer formation,6-cyano-2-naphthol,freeze concentrated solution,Fluorescence spectroscopy
更新于2025-09-23 15:19:57
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Toward efficient polymer solar cells with thick bulk heterojunction by introducing iridium complex as an aggregation reshaping auxiliary
摘要： The morphology control of thick bulk heterojunction (BHJ) polymer solar cells (PSCs) is an important factor to determine their power conversion efficiency (PCE). Particularly, during the building of phase separation, aggregation morphology plays a prominent role in the control of both horizonal and vertical gradient distribution of donor/acceptor (D/A) in thick BHJ. In this work, we introduced a novel iridium complex of (tfmppy)2Ir(tpip) into the active layer of PffBT4T-2OD: PC71BM as an “aggregation reshaping auxiliary” to form a long and narrow aggregation shape in both horizontal and vertical directions. Through characterizing the morphology of active layer in details, it was found that the combination of 5% (tfmppy)2Ir(tpip) assists PffBT4T-2OD aggregation shape with a 1: 2.5 aspect ratio while maintaining high crystallinity. In addition, the results showed that the (tfmppy)2Ir(tpip) facilitates efficient exciton dissociation and charge transport because of increased contacting area of D/A interface. As a result, the short circuit current (JSC) and fill factor (FF) performances were both improved contemporaneously, leading to a 20.3% enhancement in PCE.
关键词： Charge transport,Polymer solar cells,Thick bulk heterojunction,Aggregation reshaping auxiliary,Iridium complex
更新于2025-09-23 15:19:57
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Molecular Engineering of Acceptors to Control Aggregation for Optimized Nonfullerene Solar Cells
摘要： Dual molecular engineering on alkyl side chains and halgen accepting ends of asymmetric fused-ring acceptors has been proposed for controlling aggregation to optimized organic solar cells (OSCs). Fluorination or chlorination on end-capped group are explored along with linear octyl (C8) or branched 2-butyl-1-octyl chain (BO) substitution on donating core. The inherent features of larger Cl atom and longer C–Cl bond markedly extend the backbone stacking area and thus enhance molecular aggregation, while bulky BO chain exerts heavier steric shielding effect on backbone stacking. Consequently, IPTBO-4Cl shows properly weakened intermolecular interaction for balanced molecular aggregation. IPTBO-4Cl when blended with PM6 polymer donor delivers a highest power conversion efficiency (PCE) of 15% and with 72.6% fill factor (FF). Expectedly, fluorinated IPT-4F bearing shorter C8 chains outputs a good PCE nearing 15% with 74.2% FF. To the best of our acknowledge, the PCE of 15% is by far the highest for asymmetric FRAs based OSCs. By contrast, IPT-4Cl and IPTBO-4F with either excessively strong or weak aggregation result in relatively low photovoltaic performance. Our results demonstrate controlling aggregation via delicate molecular engineering is an undeniably effective way to achieve efficient OSCs.
关键词： Molecular Engineering,Acceptors,Aggregation,Nonfullerene Solar Cells
更新于2025-09-23 15:19:57
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Efficient Aggregation-Induced Delayed Fluorescence Luminogens for Solution-Processed OLEDs With Small Efficiency Roll-Off
摘要： Purely organic small molecules with thermally-activated delayed fluorescence have a high potential for application in organic light-emitting diodes (OLEDs), but overcoming severe efficiency roll-off at high voltages still remains challenging. In this work, we design and synthesize two new emitters consisting of electron-withdrawing benzoyl and electron-donating phenoxazine and 9,9-dihexylfluorene. Their electronic structures, thermal stability, electrochemical behaviors, photoluminescence property, and electroluminescence performance are thoroughly investigated. These new emitters show weak fluorescence in dilute solution, but they can emit strongly with prominent delayed fluorescence in the aggregated state, indicating the aggregation-induced delayed fluorescence (AIDF) character. The solution-processed OLEDs based on the two emitters show high external quantum efficiency of 14.69%, and the vacuum-deposited OLEDs can also provide comparable external quantum efficiency of 14.86%. Significantly, roll-offs of the external quantum efficiencies are very small (down to 0.2% at 1,000 cd m?2) for these devices, demonstrating the evidently advanced efficiency stability. These results prove that the purely organic emitters with AIDF properties can be promising to fabricate high-performance solution-processed OLEDs.
关键词： thermally activated delayed fluorescence,aggregation-induced fluorescence,efficiency roll-off,delayed fluorescence,organic light-emitting diodes,electroluminescence
更新于2025-09-23 15:19:57