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Hierarchical ZnO microspheres embedded in TiO2 photoanode for enhanced CdS/CdSe sensitized solar cells
摘要： Control of structural and compositional characteristics of photoanodes is a crucial step toward rapid transport of charges and high efficiency loading of dye or quantum dots in case of solar cell application. A hierarchical ZnO microspheres (ZMS) and TiO2 hybrid photoanode film was prepared for improved CdS/CdSe quantum dot sensitized solar cells (QDSCs). The addition of ZMS into TiO2 electrode films resulted in both increased short circuit current density (Jsc) and open circuit voltage (Voc). Such an improvement is ascribed to the increased light harvesting owing to scattering by ZMS and the reduced charge recombination due to the surface modification. TiO2/ZMS hybrid photoanode displays superior charge injection/transport performance due to the ZMS with unique hierarchical structure, providing charge transfer continuity and multiple electron transport channels for timely electron transport. As a result, the Jsc, Voc, and the photovoltaic conversion efficiency (PCE) were all remarkably enhanced with the insertion of hierarchical ZMS though varied appreciably with the amount of ZMS. Thus, the designed TiO2/ZMS heterostructure based QDSCs with an optimizing ZMS ratio of 20 wt% achieved a PCE of 5.99%, which is about 35% increase of the efficiency for the devices without ZMS (4.45%).
关键词： electron transport,ZnO microspheres,charge injection,quantum dot-sensitized solar cells,photoanode,light scattering
更新于2025-11-14 17:04:02
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Alcohol-Guided Growth of Two-Dimensional Narrow-Band Red-Emitting K2TiF6:Mn4+ for White Light-Emitting Diodes
摘要： The use of red phosphors with low light-scattering loss could improve the luminous efficacy and color rendering of white light-emitting diodes (LEDs). Thus, the discovery of such phosphors is highly desired. In this work, high-efficiency two-dimensional red-emitting K2TiF6:Mn4+ (KTFM) were synthesized via an alcohol-assisted coprecipitation route. The synergistic effects of 1-propanol and hydrofluoric acid (HF) on the growth of KTFM microsheets (MSs) were studied through the first-principles calculations, which revealed that 1-propanol promoted the growth of KTFM MSs by preferentially adsorbing on the H-terminated K2TiF6 (001) surface. The photoluminescence quantum efficiency (QE) of Mn4+-activated K2TiF6 MSs was highly related to their size and thickness. The morphology-optimal KTFM MSs presented high internal QE (> 90 %), external QE (> 71%), and thermal quenching temperature (102% at 150 °C relative to that at 25 °C). A prototype phosphor-converted LED with KTFM as the red-emitting component showed an excellent color rendition (Ra = 91, R9 = 79) and high luminous efficacy (LE =156 lm/w).
关键词： light emitting diode,two-dimensional material,Narrow band,K2TiF6:Mn4+,backlight,red emission
更新于2025-11-14 17:04:02
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In-situ solid phase thermal transformation of self-assembled melamine phosphotungstates produce efficient visible light photocatalysts
摘要： Visible-light-driven stacked-layer heterogeneous photocatalyst carbonitride/tungstophosphate (TCN) was constructed via in-situ solid-state thermal transformation using melamine phosphotungstate (MPW). The structural, morphological and optical properties of the samples were investigated. Compared to the MPW hybrids and phosphotungstic acid hydrate, the TCN photocatalysts showed excellent visible light photocatalytic activity. During the thermal transformation, the melamine molecules polymerize to form the defective heptazine structure carbonitride attached to the surface of mixed-valence Keggin units. The interfacial POMs anions-p interactions, ligand-to-metal charge transfer and mix-valence organic-POMs structure makes the electrons fully delocalized over the MPW hybrids, and the TCN photocatalysts obtain the extended light absorption. The Keggin units accept and transfer electrons, so the recombination of photogenerated carriers is suppressed. 13TCN-390 obtains the optimal photocatalytic activity, its photocatalytic degradation efficiency of imidacloprid and rate constant k are 6.38 and 13.50 times than that of CN-390, respectively. The enhanced photocatalytic activity arises from the extended light absorption, suppressed photogenerated carriers’ recombination, surface structure defect and suitable band structure. h+ and (cid:1)OH are the main reactive species when the proposed photocatalytic mechanism was done. This study provides a promising construction strategy for polymer/POMs photocatalysts using different organic-POMs hybrids.
关键词： Melamine phosphotungstate,Visible-light-driven photocatalyst,Degradation,Thermal transformation
更新于2025-11-14 17:04:02
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Facile microwave synthesis of carbon dots powder with enhanced solid-state fluorescence and its applications in rapid fingerprints detection and white-light-emitting diodes
摘要： In this report, we successfully developed a simple and fast MW-assisted method for preparing CDs with strong solid-state fluorescence (SSF) by using phthalic acid and piperazine as precursors. The prepared p-CDs can be obtained in high yield (48.7%) and emit bright yellow-green SSF under 365 nm UV light. The absolute PL quantum yield (PLQY) of p-CDs in solid state was measured to be 20.5%, which is much higher than that in aqueous solution. This interesting phenomenon shows that p-CDs not only successfully conquer the aggregation-caused fluorescence quenching (ACQ) effect, but also achieve enhanced fluorescence emission, which was rarely reported in previous literatures as CDs in solid state always reduce their fluorescence emission due to the excessive resonance energy transfer (RET) or direct π-π interactions. In addition, the relationship between the feed ratio of precursors and optical properties of the CDs were also investigated detailedly. Based on their strong SSF, the p-CDs were successfully used in rapid latent fingerprints detection and white light-emitting diodes (WLEDs) preparation with high quality. In summary, this research not only developed a new type of CDs with strong enhanced SSF, but also offered a valuable reference for design SSF-emitting CDs with high yield.
关键词： Carbon dots,Solid-state fluorescence,Light-emitting diodes,Latent fingerprints
更新于2025-11-14 17:04:02
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Plasmonic Au nanoparticles supported on both sides of TiO2 hollow spheres for maximising photocatalytic activity under visible light
摘要： A strategy of intensifying the visible light harvesting ability of anatase TiO2 hollow spheres (HSs) was developed, in which both sides of TiO2 HSs were utilised for stabilising Au nanoparticles (NPs) through the sacrificial templating method and convex surface-induced confinement. The composite structure of single Au NP yolk-TiO2 shell-Au NPs, denoted as Au@Au(TiO2, was rendered and confirmed by the transmission electron microscopy analysis. Au@Au(TiO2 showed enhanced photocatalytic activity in the degradation of methylene blue and phenol in aqueous phase under visible light reference materials such as surpassing that of other Au(TiO2 by 77% and Au@P25 by 52%, respectively, in phenol degradation.
关键词： confinement,photocatalytic degradation,visible light,TiO2 hollow spheres,plasmonic Au nanoparticles
更新于2025-11-14 17:04:02
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Time-dependent DFT and experimental study on visible light photocatalysis by metal oxides of Ti, V and Zn after complexing with a conjugated polymer
摘要： Density Functional Theory (DFT) and Time Dependent (TD)-DFT studies predict substantial modifications in optical properties of Transition Metal Oxides (TMOs) of Ti, V and Zn by complexing them with conjugated polymer polythiophene (PTh). The TMO nanostructures were synthesized and their complexes with polymers were fabricated using a chemical oxidative polymerization method. Coating of the TMOs with PTh and the nano-dimensional nature of the samples was confirmed by various morphological investigations such as infrared (IR), X-ray di?ractographs (XRD), High Resolution Transmission Electron Microscopy (HR-TEM) and field emission scanning electron microscopy (FE-SEM) techniques. The prepared samples were found to be a visible light driven photocatalyst. The sensitization of the complexes has been explained in terms of relative ordering of frontier orbitals of PTh and the TMO, and PTh qualified as an e?cient photosensitizer for all three metal oxides on the basis of its electronic characteristics. Since the Highest Occupied Molecular Orbital (HOMO) of PTh lies well between the band gap of all three TMOs, the electron transfer from donor (PTh) to acceptor (TMO) is facilitated. The appreciable red shift in the absorption spectrum and decrease in the optical band gap calculated by Tauc’s plot confirmed substantial reduction in the band gap of the formed complex in comparison to their bare counterparts. The isodensity plots established the PTh–TMO complexes as donor acceptor complexes and intermolecular charge transfer quantified the electron transfer from PTh (donor) to the TMOs (acceptor).
关键词： conjugated polymer,TD-DFT,visible light,metal oxides,DFT,photocatalysis,polythiophene,band gap tuning
更新于2025-11-14 17:04:02
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Visible-light-triggered generation of persistent radical anions from perylenediimides: A substituent effect and potential application in photocatalytic reduction of Ag+
摘要： Three perylenediimide derivatives were reduced to their persistent radical anions in N-methyl-2-pyrrolidone (NMP) under ambient conditions by a visible light photoinduced electron transfer (PET). UV?vis and electron paramagnetic resonance (EPR) measurements were carried out to confirm the formation of radicals. The relationships between molecular structure, electrochemical property, phototransformation kinetics, and air stability of radical anions were investigated by the introduction of pyrimidine rings at the core position and fluoroalkylation substituents at the imide position. This study reveals that the electron-deficient pyrimidine rings and electron-withdrawing fluoroalkylation substituents can effectively enhance the phototransformation rate and the radical stability at ambient conditions. The effects of solvents and illuminance levels on the photoinduced reduction of perylenediimides were also studied. A photocatalytic reduction of Ag+ was successfully carried out using the perylenediimide with pyrimidine and fluoroalkylation substituents as catalyst upon irradiation with visible light.
关键词： Photocatalytic reduction,Perylene diimide derivative,Silver ion,Persistent radical anion,Visible light irradiation
更新于2025-11-14 17:03:37
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Construction of a high-performance photocatalytic fuel cell (PFC) based on plasmonic silver modified Cr-BiOCl nanosheets for simultaneous electricity production and pollutant removal
摘要： The development of high-performance photocatalytic fuel cell (PFC) is seriously hampered by the poor light utilization rate and low charge carriers transfer efficiency. Herein, we have experimentally obtained the plasmonic Ag modified Cr-BiOCl (Cr-BOC/Ag) with high visible light photocatalytic activity and provided direct evidence for the substantially enhanced catalytic activity in metal-semiconductor photocatalysts. The experimental results revealed that the Cr doping and Ag modification could not only extend the photo absorption of BiOCl from the UV to the visible light region but also greatly increase the generation and transfer rate of charge carriers because of its narrowed band gap and the localized surface plasmon resonance (LSPR) effect of metallic Ag. Under visible light irradiation, the Cr-BOC/Ag showed the remarked enhancement on PFC performance when the optimum contents of Cr doping and Ag loading was 14.4% and 4%, respectively. The trapping experiments and multiple characterizations demonstrated that the advantageous combination of Cr doping effect and SPR effect induced by the Ag nanoparticles is responsible for the high generation rate of oxidative species and effective charge carriers transfer. By using RhB as fuel, approximately 75.1% color removal efficiency and 8.38% Coulombic efficiency were obtained under visible light irradiation for 240 min, which are higher than that of MO and TC. And, the Jsc and Voc of Cr-BOC/Ag photoanode were measured to be 0.0073 mA/cm2 and 0.543 V.
关键词： photocatalytic degradation,SPR,BiOCl,coulombic efficiency,visible light,fuel cell
更新于2025-11-14 17:03:37
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Preparation of Ag-doped Bi5O7I composites with enhanced visible-light-induced photocatalytic performance
摘要： A novel heterostructure photocatalysts, Ag-doped Bi5O7I composites (Ag/Bi5O7I), were synthesized by a simple hydrothermal method. Compared with Bi5O7I, Ag/Bi5O7I composites had a stronger light absorption in the visible and near-infrared region and the light absorption edge of Ag/Bi5O7I composites had a slight red shift. Moreover, Ag/Bi5O7I composites possessed a higher photocatalytic activity than Bi5O7I on the degradation of rhodamine B (RhB) and methyl orange (MO) under visible-light irradiation (λ ≥ 420 nm). When the content of Ag was 1%, the degradation efficiency of the Ag/Bi5O7I composites toward RhB and MO reached the maximum value, which was about 20.2 and 7.6 times higher than that of Bi5O7I, respectively. The trapping experiments shown that superoxide radicals and holes were the main active species in the photodegradation process. The excellent photocatalytic performance could be attributed to Ag/Bi5O7I heterojunction and surface plasma resonance effect of Ag, which could increase absorption of visible light and cause the efficient separation and migration of carriers.
关键词： Ag-doped Bi5O7I,Visible-light,Surface plasma resonance,Heterostructure photocatalysts
更新于2025-11-14 17:03:37
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2D visible-light-driven TiO2@Ti3C2/g-C3N4 ternary heterostructure for high photocatalytic activity
摘要： A novel 2D visible-light-driven TiO2@Ti3C2/g-C3N4 ternary heterojunction photocatalyst with modified interfacial microstructure and electronic properties was synthesized by ultrasonic-assisted calcination method. The remarkably active g-C3N4 could provide high productivity of photogenerated electrons and holes. Meanwhile, the O/OH-terminated Ti3C2 and by-product TiO2 could act as excellent supporters by migrating electrons in TiO2@Ti3C2/g-C3N4 hybrids. As a result, the highest photocatalytic activities in the degradation of aniline and RhB were increased to 5 and 1.33 times higher than that of pristine g-C3N4 under visible-light irradiation, respectively. Furthermore, we proposed that n–n heterojunction and n-type Schottky heterojunction were built up across their interfaces, which efficiently improve the transition of electrons and further promote the photocatalytic activity of TiO2@Ti3C2/g-C3N4 hybrids. More appealingly, all the results highlight that the environment-friendly TiO2@Ti3C2/g-C3N4 heterojunction hybrids would be desirable candidates for pollutants degradation.
关键词： 2D materials,photocatalytic activity,TiO2@Ti3C2/g-C3N4,ternary heterojunction,pollutants degradation,visible-light-driven
更新于2025-11-14 17:03:37