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Solar-driven hydrogen (H2) generation from seawater exhibits great economic value in addressing the urgent energy shortage yet faces challenges from the severe salt-deactivation effect, which could result in the consumption of pho...
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Solar-driven hydrogen (H2) generation from seawater exhibits great economic value in addressing the urgent energy shortage yet faces challenges from the severe salt-deactivation effect, which could result in the consumption of photoinduced charges and decomposition of catalysts. Herein, a triptycene-based polymer was coated on the surface of a CdxZn1-xS nanorod to form a core-shell heterojunction (TCP@CZS) by using the in situ Suzuki reaction for photocatalytic H2 production from water/seawater splitting. The introduction of TCP can provide a large surface area, enrich the active site, and boost charge transfer for the proton reduction reaction. Benefiting from it, optimal TCP@CZS indicated a H2 evolution rate of 93.88 mmol h-1 g-1 with Na2S/Na2SO3 in natural seawater under simulated solar light irradiation, which was 2.2 and 1.1 times higher than that of pure Cd0.6Zn0.4S and that in pure water, respectively. Besides, the apparent quantum efficiency (AQE) of TCP@CZS-3 under 420 nm light irradiation was 22.6% in seawater. This work highlights the feasibility of the triptycene-based porous organic polymer as an efficient catalyst for solar energy conversion in seawater.
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Using sol-gel auto-combustion combined with calcination, spinel zinc ferrite (ZnFe2O4) and monoclinic bismuth vanadate (m-BiVO4) nanopowder were synthesised. On this basis, novel heterojunction-structure monoclinic bismuth vanadat...
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Using sol-gel auto-combustion combined with calcination, spinel zinc ferrite (ZnFe2O4) and monoclinic bismuth vanadate (m-BiVO4) nanopowder were synthesised. On this basis, novel heterojunction-structure monoclinic bismuth vanadate/spinel ferrite ZnFe2O4 (BZF) composites were prepared, for the first time, using sol-gel combined with in situ loading. The characteristics of as-prepared materials were ascertained by X-ray diffraction spectroscopy, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy and ultraviolet-visible diffuse reflectance spectroscopy. As-prepared pure ZnFe2O4 particles were short, rodlike and about 100-200 nm. Pure m-BiVO4 powder was spindle-like, distributed uniformly and about 150-250 nm. BZF composites were used to degrade methylene orange (MO) under visible-light irradiation. Among as-prepared BZF composites, BZF-15 wt% had optimal photocatalytic activity for degrading MO. The photocatalytic mechanism of the composites was attributed to the effective separation between photo-generated electrons and holes based on the heterojunction energy-band theory.
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The problem of electron tunneling in an electric field through a potential barrier doped with shallow traps has been solved. The transmission coefficient and current-voltage characteristics (CVC) of this system have been calculate...
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The problem of electron tunneling in an electric field through a potential barrier doped with shallow traps has been solved. The transmission coefficient and current-voltage characteristics (CVC) of this system have been calculated for different sets of-system parameters. It is shown that the current-voltage characteristics of the given system have a region with negative differential resistance, that depends on the depth of the impurity level. [References: 8]
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The stability of structures consisting of p-type high-resistivity epitaxial layers of CdTe grown by metal-organic chemical vapour deposition technology was studied by monitoring the capacitance and the AC and DC conductances of st...
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The stability of structures consisting of p-type high-resistivity epitaxial layers of CdTe grown by metal-organic chemical vapour deposition technology was studied by monitoring the capacitance and the AC and DC conductances of structures. The structures were grown on substrates differing in their conductivity type and composition. The structure parameters were measured in the frequency range 0.5-1000 kHz immediately after fabrication, after storage for half a year in the dark at room temperature and after ultrasonic processing. It was found that the stability of the epilayer parameters against ageing and acoustic treatments depended strongly on the substrate characteristics. The ageing and the epilayer degradation due to the ultrasonic processing were found to be a result of the diffusion of mobile acceptor defects from the substrate to the epilayer. The highest electric parameter stability was found for the epi-CdTe/n-CdTe structure. It is shown that the main reason for this stability is the potential barrier at the p-n junction, which prevents the acceptor defects from diffusing out of the substrate. [References: 22]
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The reported antimony selenide (Sb2Se3) photodetectors (PDs) are still far away from color camera applications mainly due to the high operation temperature required in chemical vapor deposition (CVD) and the lack of high-density P...
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The reported antimony selenide (Sb2Se3) photodetectors (PDs) are still far away from color camera applications mainly due to the high operation temperature required in chemical vapor deposition (CVD) and the lack of high-density PD arrays. In this work, we propose a Sb2Se3/CdS/ZnO PD created by physical vapor deposition (PVD) operated at room temperature. Using PVD, a uniform film can be obtained, so the optimized PD has excellent pho-toelectric performance with high responsivity (250 mA/W), high detectivity (5.6 x 1012 Jones), low dark current (similar to 10-9 A), and short response time (rise: < 200 )s; decay: < 200 )s). With the help of advanced computational imaging technol-ogy, we successfully demonstrate color imaging applications by the single Sb2Se3 PD; thus, we expect this work can bring Sb2Se3 PDs in color camera sensors closer. (c) 2023 Optica Publishing Group
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Position sensitivity of transient photoconductivity has been observed in oxygen-deficient La-0.67(Ca0.75Ba0.25)(0.33)MnO3-delta (LCBMO) thin films at room temperature. The voltage drop across the reference resistor is sensitive to...
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Position sensitivity of transient photoconductivity has been observed in oxygen-deficient La-0.67(Ca0.75Ba0.25)(0.33)MnO3-delta (LCBMO) thin films at room temperature. The voltage drop across the reference resistor is sensitive to the position of the laser spot between the electrodes on the films. The phenomenon has been also observed in LCBMO/Si p-n junctions. The mechanism of the phenomenon is discussed. The results may have potential applications in position-sensitive photodetectors based on manganites.
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Organic heterojunctions have become a unique platform to explore superior thermoelectric performance based on the fundamental possibilities of separately controlling electrical and thermal transport throu
Organic heterojunctions have become a unique platform to explore superior thermoelectric performance based on the fundamental possibilities of separately controlling electrical and thermal transport through interfaces structured at different length scales. Particularly, the “heterojunctions” present artificially made components, in addition to each component used to form heterojunctions, to further control electrical and thermal conductions toward developing high‐performance thermoelectrics. Potentially, in organic heterojunctions, the different components (organic–organic, organic–inorganic) possess low thermal and high electrical conductivities, which present the necessary conditions for developing high thermoelectric actions. Furthermore, organic heterojunctions provide an opportunity to form electrically conductive but thermally resistive interfaces between different components at different length scales from molecular to thin‐film and hybrid designs, functioning as a third component, upon combing two components. In particular, the interface can be facilely tuned toward ultimately separating electrical and thermal conduction by rationally selecting electric, polarization and thermal parameters. In this Review, the fundamental thermoelectric properties of organic heterojunctions from molecular to thin‐film and hybrid designs are presented. The thermoelectric performances enhanced by interface effects are also highlighted. Finally, the outlook for the further thermoelectric developments is discussed.
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The basic electrical and optical properties of films made of propolis, which is a natural, biologically active, organic compound, are studied. Photoluminescence is found to exist at room temperature with a maximum at 434 nm. The c...
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The basic electrical and optical properties of films made of propolis, which is a natural, biologically active, organic compound, are studied. Photoluminescence is found to exist at room temperature with a maximum at 434 nm. The conduction activation energy in the temperature range 283-300 K is 2.9 eV and correlates with the optical band gap. (C) 2004 MAIK "Nauka/Interperiodica".
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Hybrid heterojunction cell based on thermally evaporated 5,10,15,20-tetraphenyl-21H, 23H-porphine iron (III) chloride (FeTPPCl) as the organic semiconductor and p-Si wafer as the inorganic semiconductor have been investigated. Thi...
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Hybrid heterojunction cell based on thermally evaporated 5,10,15,20-tetraphenyl-21H, 23H-porphine iron (III) chloride (FeTPPCl) as the organic semiconductor and p-Si wafer as the inorganic semiconductor have been investigated. This device showed rectification behaviour like diode. The conduction mechanisms and the diode parameters have been studied using current-voltage (7-V) characteristics in the temperature range (298-373 K) and capacitance-voltage (C-V) characteristics at room temperature. This cell exhibited photovoltaic characteristics with a short-circuit current (I_(sc)) of 2.8 mA, an open-circuit voltage (V_(oc)) of 0.475 V, a fill factor FF= 32%.
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The development of novel, efficient and stable catalysts for CO2 photoreduction is highly anticipated. In this work, a series of 0D/2D CsPbBr3/BiVO4 composites were prepared by simple self-assembly of 0D CsPbBr3 quantum dots and 2...
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The development of novel, efficient and stable catalysts for CO2 photoreduction is highly anticipated. In this work, a series of 0D/2D CsPbBr3/BiVO4 composites were prepared by simple self-assembly of 0D CsPbBr3 quantum dots and 2D BiVO4 nanosheets. It was discovered that the photocatalytic CO2 reduction activities of asprepared CsPbBr3/BiVO4 catalysts were greatly improved when exposed to visible light. For the optimal sample, the average CO production could achieve 41.02 mu mol.g(-1).h(-1), and the photocatalytic performance is 7 and 4 times that of original BiVO4 and CsPbBr3, respectively. Additionally, the sample exhibited high stability in the cycle test. According to the comprehensive characterization test and analysis results, the enhanced CO2 photoreduction performances are attributed to the composites' increased light absorption capacity and noticeably accelerated charge carrier separation and transfer efficiency. The special S-scheme photocatalytic mechanism of CsPbBr3/BiVO4 hybrids is proposed and discussed in detail on the basis of the electron spin resonance results and the energy band structure theory. This work provides new opportunities for designing S-scheme heterojunctions based on lead halide perovskite with high photocatalytic activity.
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