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Probe and Control of the Tiny Amounts of Dopants in BHJ Film Enable Higher-Performance Polymer Solar Cells
摘要： In order to achieve efficient doping in polymer solar cell (PSC), the dopant needs to be selectively located in the binary components of bulk heterojunction (BHJ) film according to its polarity. The rarely studied n-type dopant is thoroughly examined in a simplified planar heterojunction (PHJ) device to address its favored location in the active layer. Results show that the n-dopant distributing in the acceptor layer or at the donor/acceptor interface produces enhanced device performance, whereas it harms the device when locating in the donor layer. Based on the results, the benefit of n-type doping is then transferred to the high-efficient BHJ devices via a sequential coating procedure. The performance improvement is closely linked with the variation of dopant’s location in the BHJ film, which is carefully examined by the synchrotron techniques with delicate chemical sensitivity. More interestingly, the sequential coating procedure can be easily extended to the p-doped device only by changing the dopant’s polarity in the middle layer. These findings pave the way of ambipolar doping in PSCs and make performance improvement by molecular doping within expectation.
关键词： molecular doping,Polymer solar cell,doped morphology,n-type doping,ternary blend solar cell
更新于2025-09-23 15:21:01
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Role of Morphology of Surfactant-Free Nanoparticles in Organic Photovoltaics
摘要： Nanoparticulate (NP) ?lms and organic photovoltaic devices have been fabricated from poly(3-hexylthiophene):phenyl C61 butyric acid methyl ester (P3HT:PC61BM) NP aqueous dispersions prepared by the precipitation method. The NP inks were stable for more than 4 days, and nanoparticle organic photovoltaic (NP-OPV) devices with ef?ciency (g) of 1% were fabricated. Detailed analysis of the morphology and performance of the precipitated NP-OPV devices indicated that an optimal blend is responsible for the photocurrent and ef?ciency observed. These results were con?rmed by grazing-incidence x-ray diffraction (GIXRD) analysis, which revealed that the precipitated NPs were resistant to thermal phase segregation, allowing thermal conditioning of the NP ?lms. These results show that precipitated NPs provide a pathway to thermally stable NP-OPV devices with higher photocurrents and ef?ciencies, approaching those of optimal bulk heterojunction (BHJ) OPV devices.
关键词： ink stability,Organic photovoltaic cells (OPV),nanoparticle (NP),nanoparticle morphology,precipitation,surfactant-free
更新于2025-09-23 15:21:01
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Puffing quaternary FexCoyNi1-x-yP nanoarray via kinetically controlled alkaline etching for robust overall water splitting; ?￠±???è???3??????oè?¨???FexCoyNi1a??xa??yP??????é?μ?????????é?? ???è￡?è§￡?°′??§è??;
摘要： Designing and constructing bifunctional electrocatalysts with high efficiency, high stability and low cost for overall water splitting to produce clean hydrogen fuel is attractive but highly challenging. Here we constructed puffed quaternary FexCoyNi1?x?yP nanoarrays as bifunctional electrodes for robust overall water splitting. The iron was used as the modulator to manipulate the electron density of NiCoP nanoarray, which could increase the positive charges of metal (Ni and Co) and P sites. The resultant electronic structure of FexCoyNi1?x?yP was supposed to balance the adsorption and desorption of H and accelerate the oxygen evolution reaction (OER) kinetics. Moreover, the morphological structure of FexCoyNi1?x?yP was modulated through the kinetically controlled alkaline etching by using the amphoteric features of initial FeCoNi hydroxide nanowires. The resultant puffed structure has rich porosity, cavity and defects, which benefit the exposure of more active sites and the transport of mass/charge. As a result, the cell integrated with the puffed quaternary FexCoyNi1?x?yP nanoarrays as both the cathode and anode only requires the overpotentials of 25 and 230 mV for hydrogen evolution reaction (HER) and OER at the current density of 10 mA cm?2 in alkaline media and a cell voltage of 1.48 V to drive the overall water splitting. Moreover, the puffed FexCoyNi1?x?yP demonstrates remarkable durability for continuous electrolysis even at a large current density of 240 mA cm?2.
关键词： water splitting,puffed nanoarray,electrocatalysis,morphology control,alkaline etching
更新于2025-09-23 15:21:01
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Magneto-optical properties of Rare Earth metals substituted Co-Zn spinel nanoferrites
摘要： Cobalt–zinc ferrite nanoparticles (NPs) substituted with three different metals, Co0.5Zn0.5RexFe2-xO4 (RE = Ce, Dy, and Y; 0.00 ≤ x ≤ 0.05) were prepared hydrothermally. Fourier Transform-Infrared (FT-IR) Spectroscopy, X-ray powder diffraction (XRD), Field-Emission Scanning Electron Microscope (FESEM) coupled with energy-dispersive X-ray spectroscopy (EDX) and Vibrating Sample Magnetometry (VSM) analyzed the products. The formation of cubic phase of spinel Co-Zn ferrite NPs were confirmed through XRD, FT-IR and FE-SEM techniques. The structural investigation of NPs by XRD revealed that the lattice parameter "a" decreases with the introduction of the RE in the ferrite structure by the substitution of Fe3+ by RE ions. The different magnetic parameters of Co0.5Zn0.5RexFe2-xO4 (RE = Ce, Dy, and Y; 0.00 ≤ x ≤ 0.05) NPs such as the saturation magnetization, coercivity, remanence, and magnetic moment were calculated and discussed in relation to structure and microstructure properties. M (H) hysteresis curves indicated that the samples exhibit superparamagnetic nature at room temperature. A slight improvement in the magnetization was obtained especially for the Ce- and Y-substituted Co0.5Zn0.5Fe2O4 (CZF) NPs at a certain RE level. However, the case Dy-substituted CZF products showed a sharp decrease in the magnetization with x > 0.01. The results are mostly ascribed to the substitution of smaller Fe3+ ions with larger RE3+ ions.
关键词： Spinel ferrites,Morphology,Rare earth substitution,Hydrothermal,Magnetic properties
更新于2025-09-23 15:21:01
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Tackling Performance Challenges in Organic Photovoltaics: An Overview about Compatibilizers
摘要： Organic Photovoltaics (OPVs) based on Bulk Heterojunction (BHJ) blends are a mature technology. Having started their intensive development two decades ago, their low cost, processability and flexibility rapidly funneled the interest of the scientific community, searching for new solutions to expand solar photovoltaics market and promote sustainable development. However, their robust implementation is hampered by some issues, concerning the choice of the donor/acceptor materials, the device thermal/photo-stability, and, last but not least, their morphology. Indeed, the morphological profile of BHJs has a strong impact over charge generation, collection, and recombination processes; control over nano/microstructural morphology would be desirable, aiming at finely tuning the device performance and overcoming those previously mentioned critical issues. The employ of compatibilizers has emerged as a promising, economically sustainable, and widely applicable approach for the donor/acceptor interface (D/A-I) optimization. Thus, improvements in the global performance of the devices can be achieved without making use of more complex architectures. Even though several materials have been deeply documented and reported as effective compatibilizing agents, scientific reports are quite fragmentary. Here we would like to offer a panoramic overview of the literature on compatibilizers, focusing on the progression documented in the last decade.
关键词： mixing interfaces,additives,bulk heterojunction,morphology modulators,donor/acceptor interface,organic photovoltaics,compatibilizers
更新于2025-09-23 15:21:01
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Tunable luminescence and morphological evolution of facile synthesized zinc borate/carbon dots composites for NUV-WLEDs
摘要： A series of zinc borate/carbon dots composites (ZBH/yNCDs) were successfully synthesized under hydrothermal conditions. The influences of yellow N-doped carbon dots (yNCDs) content on the structure, morphologies and luminescence properties of the zinc borate (4ZnO·B2O3·H2O, ZBH) were investigated. With increasing yNCDs content, ZBH in the ZBH/yNCDs composites gradually lost water and eventually became ZB/yNCDs (4ZnO·B2O3, ZB) composites. Meanwhile, the tunable luminescence of ZBH/yNCDs composites and the morphological evolution from rod-like to blocks to sphere-like were achieved by varying the yNCDs content in the zinc borate matrix. The results revealed that the ZBH/yNCDs composite with sphere-like morphology has the strongest white light emission at 395 nm excitation wavelength. Therefore, the ZBH/yNCDs composites may be used as phosphors in the near-ultraviolet (NUV) excitation white-light illumination field. The discovery of this work may also provide new inspirations for solving the self-quenching effect of carbon dots in the solid-state display applications.
关键词： N-doped carbon dots,White light-emitting diodes,Morphology,Zinc borate
更新于2025-09-23 15:21:01
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Synergetic interface and morphology modification to achieve highly efficient solution-processed sky-blue organic light-emitting diodes
摘要： Solution-processed organic light-emitting diodes (OLEDs), especially blue OLEDs, generally suffer from the low efficiency. Herein, we report an efficient approach to achieve high efficiency by synergetic interface and morphology modification with a polymer, Poly(9-vinylcarbazole) (PVK). Sky-blue thermally activated delayed fluorescent (TADF) material, 10-(4-(4,6-diphenyl-1,3,5- triazin-2-yl)phenyl)-10H- spiro[acridine-9,9-fluorene] (SpiroAC-TRZ), is used as the emitter. The incorporation of PVK thin layer at the hole injection layer/emission layer (EML) interface and a small amount of PVK inner the EML modify the carrier behaviors at the interface and improve the EML morphology. As a result, balanced carrier distribution and reduced carrier recombination are realized at the interface and inner the EML. Through these strategies, the maximum external quantum efficiency and current efficiency of the optimal OLED achieve 25.1% and 53.5 cd/A. To the best of our knowledge, the efficiencies are the highest values ever achieved by the solution-processed sky-blue TADF OLEDs.
关键词： Blue organic light-emitting diodes,Thermally activated delayed fluorescence,High efficiency,All-solution process,Film morphology
更新于2025-09-23 15:21:01
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The morphology regulation and plasmonic spectral properties of Au@AuAg yolk-shell nanorods with controlled interior gap
摘要： Au@AuAg yolk-shell nanorods with tunable and uniform interior gap were synthesized through galvanic replacement reaction, where Au@Ag core-shell nanorods served as sacrificial templates and HAuCl4 solution served as reductant. The effects of HAuCl4, Ag shell thickness and aspect ratio (AR) of Au nanorods on the morphology of Au@AuAg yolk-shell nanorods had been investigated systemically. The results clearly indicated that AuAg alloy shell thickness of Au@AuAg yolk-shell nanorods could be increased from 3.6 to 10.0 nm by varying the amount of HAuCl4. Meanwhile, the shape of AuAg alloy shell could be tuned by changing the shape of Ag coating. With the increasing of Ag coating thickness, the interior gap could be finely tuned in the range from 2.6 to 8.1 nm. The uniformity of interior gap could be improved by increasing the AR of Au nanorods. All these tunable geometries can further affect the plasmonic spectral properties of Au@AuAg yolk-shell nanorods. Because of the appearance of interior gap, the longitudinal localized surface plasmon resonance (LSPR) peak of Au@AuAg yolk-shell nanorods was located between that of bare Au nanorods and Au@Ag core-shell nanorods without interior gap. The increase of outer AuAg shell thickness can weaken the coupling between the inner and outer surface of the AuAg shell and lead to the decrease of AR, so the transverse and longitudinal LSPR bands gather together. The decrease of Ag coating thickness can enhance the coupling between inner Au nanorod and outer AuAg shell, which results in the red shift of the longitudinal LSPR band. This paper provides a method for studying the plasmonic coupling between two metal surfaces with a metal layer or a dielectric layer, which is also a new approach for regulating the plasmonic spectral properties of bimetallic nanoparticles. The controllability of Au@AuAg yolk-shell nanorods in both the interior gap and outer alloy shells makes them have potential applications in biomedicine, catalysis, nanoreactors, and energy storage.
关键词： interior gap,localized surface plasmon resonance,spectral properties,morphology regulation,Au@AuAg yolk-shell nanorods
更新于2025-09-23 15:21:01
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Effects of lithium doping on: microstructure, morphology, nanomechanical properties and corrosion behaviour of ZnO thin films grown by spray pyrolysis technique
摘要： Li-doped ZnO thin films were prepared on glass substrate by a chemical spray pyrolysis method, in the temperature of 460 °C. The effects of Li content on the microstructural, morphological and mechanical characteristics of the doped (ZnO:Li) thin films were also examined. The XRD study showed a sharp preferred c-axis orientation and showed that (ZnO:Li) films have a würtzite structure and grow principally along the c-axis orientation with a preferred orientation (002). The film morphology was examined by (AFM) and (SEM). Results of SEM observations showed that sprayed thin films, exhibited uniform and harmonious texture. Furthermore, ZnO:Li thin films revealed uniform and spherical shaped crystallites with an approximate medium size of 200 nm. AFM characterization demonstrated an amelioration of the surface roughness of the ZnO:Li thin films. The mechanical characteristics of ZnO:Li thin films have been investigated by the nano-indentation experiment. It has been found that the addition of lithium enhances the hardness and Young’s modulus. On the other hand, the corrosion behaviour of Li-doped thin films is examined in chloride solutions. The electrochemical experiments confirmed that the lithium doping could ameliorate the anti-corrosion performance.
关键词： nanomechanical properties,morphology,microstructure,spray pyrolysis,thin films,Li-doped ZnO,corrosion behaviour
更新于2025-09-23 15:21:01
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Evolution of Morphology, Phase Composition and Photoluminescence of Cesium Lead Bromine Nanocrystals with Temperature and Precursors
摘要： Compared with CsPbBr3 nanocrystals (NCs), the study of the structure and physical properties of Cs4PbBr6 and CsPb2Br5 NCs is not sufficient. In this paper, CsPbBr3, CsPb2Br5, and Cs4PbBr6 NCs were prepared by a hot-injection method using oleylamine (OAm) and oleic acid (OA) without adding other ligands. The evolution of phase composition, morphology and photoluminescence (PL) property were investigated. It is found that rhombohedral Cs4PbBr6 was created at low temperature with low Pb/Cs ratios and short reaction time. CsPbBr3 phase was then obtained with increasing Pb/Cs ratios at high temperature through the reaction of Cs4PbBr6 and PbBr2. The evolution of phase composition occurred with time to create CsPbBr3, CsPb2Br5, and Cs4PbBr6 NCs. For a Pb/Cs molar ratio of 3, CsPbBr3 were firstly obtained at 180 °C. However, resulting sample is CsPb2Br5 phase after 120 min. The excesses PbBr2 is a key for such phase change because no similar phenomenon was observed in the case of molar ratio of Pb/Cs of 2. At low temperature (e.g. 140 and 160 °C), rhombohedral Cs4PbBr6 phase was obtained and then reacted with PbBr2 to fabricate cubic CsPbBr3 nanosheets with sizes of several hundred nanometers. With changing phase composition, cubic, rod, rhombohedral morphologies were created. The PL properties of the NCs depended strongly on the phase composition. As a result, CsPbBr3 NCs reveal highly bright PL with narrow and symmetrical PL spectra (PL peak at 520 nm). In contrast, No PL was observed for Cs4PbBr6 and CsPb2Br5 phases. The results provide a possibility to well control the growth for the application of cesium lead halide NCs.
关键词： Cesium lead bromine nanocrystals,Photoluminescence,Morphology,Phase evolution,Hot-injection method
更新于2025-09-23 15:21:01