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Bacteria functionalized gold nanoparticle matrix based fiber-optic sensor for monitoring heavy metal pollution in water
摘要： In the present study, E.coli B40 bacteria were explored as possible receptors on localized surface plasmon resonance (LSPR) based biosensor for sensing heavy metal ions viz. mercury (Hg2+) and cadmium (Cd2+) in water. The E.coli B40 bacteria were immobilized on gold nanoparticles (AuNP) coated fiber-optic probes by depositing two bi-layers of oppositely charged polyelectrolytes. The E.coli immobilized sensor probes were subjected to different concentrations of Hg2+ and Cd2+ ions, ranging from 0.5 ppb to 2000 ppb. These metal ions interact with the thiols and other surface groups present on the bacterial cells, resulting in the change of refractive index around AuNP coated sensor probes, thereby modulating the sensor response. The detection was performed by spiking de-ionized (DI) water and tap water with metal ions and the limit of detection was found to be 0.5 ppb. The proposed sensor could detect heavy metal ions within 10 min from a small sample (< 1 ml) and showed good selectivity towards heavy metal ions over other transition metal ions. Control studies performed using amino acids like cysteine as receptors were found to be less sensitive than the proposed scheme using bacterial cells.
关键词： polyelectrolytes,fiber-optic sensor,Bacteria,gold nanoparticles,heavy metal ions,localized surface plasmon resonance
更新于2025-09-23 15:21:01
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Tailoring Perovskite Adjacent Interfaces by Conjugated Polyelectrolyte for Stable and Efficient Solar Cells
摘要： Interface engineering is an effective means to enhance the performance of thin film devices, such as perovskite solar cells (PSCs). Here, a conjugated polyelectrolyte, poly[(9,9-bis(3'-((N,N-dimethyl)-N-ethyl-ammonium)-propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)]di-iodide (PFN-I), is employed at the interfaces between the hole transport layer (HTL)/perovskite and perovskite/electron transport layer (ETL) simultaneously, to enhance the device power conversion efficiency (PCE) and stability. The fabricated PSCs with an inverted planar heterojunction structure show improved open-circuit voltage (Voc), short-circuit current density (Jsc) and fill factor (FF), resulting in PCEs up to 20.56%. The devices maintain over 80% of their initial PCEs after 800 hours of exposure to a relative humidity 35-55 % at room temperature. All of these improvements are attributed to the functional PFN-I layers as they provide favorable interface contact and defect reduction.
关键词： perovskite solar cells,non-radiative recombination,conjugated polyelectrolytes,interface engineering
更新于2025-09-23 15:19:57
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Efficient Polymer Solar Cells Employing Solutiona??Processed Conjugated Polyelectrolytes with Differently Charged Side Chains
摘要： Poly(6-(4,7-dimethyl-2H-benzo[d][1,2,3]triazol-2-yl)-N,N,N-trimethylhexan-1 aminium iodide) (PBTz-TMAI) and poly(sodium 4-(4,7-dimethyl-2H-benzo[d][1,2,3]triazol-2-yl)butane-1-sulfonate) (PBTz-SO3Na) based on the same benzotriazole-conjugated backbone but with ammonium and sulfonated side chains are designed and synthesized through side-chain functionalization and Yamamoto polymerization, respectively, and are used as the cathode interlayers in fullerene- and non-fullerene-based polymer solar cells. The interfacial modification of PBTz-TMAI and PBTz-SO3Na onto the active layer achieves good energy alignment at cathode electrodes and optimized exciton-dissociation efficiency from the active layer. Consequently, the power conversion efficiencies (PCEs) of 7.8% and 9.6% are obtained for the fullerene PTB7:PC71BM-based and non-fullerene PBDB-T:ITIC-based polymer solar cells (PSCs) with PBTz-SO3Na interlayer. The PCS devices based on PTB7:PC71BM and PBDB-T:ITIC active layers with PBTz-TMAI interlayer achieved a remarkably improved performance with PCEs of 8.2% and 10.2%, respectively.
关键词： cathode interlayers,polymer solar cells,conjugated polyelectrolytes
更新于2025-09-23 15:19:57
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Composite Interlayer Consisting of Alcohol-Soluble Polyfluorene and Carbon Nanotubes for Efficient Polymer Solar Cells
摘要： We report the synthesis of composite interlayers using alcohol-soluble polyfluorene (ASP)-wrapped single-walled carbon nanotubes (SWNTs) and their application as electron transport layers for efficient organic solar cells. The ASP enables the individual dispersion of SWNTs in solution. The ASP-wrapped SWNT solutions are stable for 54 days without any aggregation or precipitation, indicating their very high dispersion stability. Using the ASP-wrapped SWNTs as a cathode interlayer on zinc oxide nanoparticles (ZnO NPs), a power conversion efficiency of 9.45% is obtained in PTB7-th:PC71BM-based organic solar cells, which is mainly attributed to the improvement in the short circuit current. Performance enhancements of 18% and 17% are achieved compared to those of pure ZnO NPs and ASP on ZnO NPs, respectively. In addition, the composite interlayer is applied to non-fullerene-based photovoltaics with PM6:Y6, resulting in the PCE up to 14.37%. The type of SWNT (e.g., in terms of diameter range and length) is not critical to the improvement in the charge-transport properties. A low density of SWNTs in the film (~1 SWNTs/μm2 for ASP-wrapped SWNTs) has a significant influence on the charge transport in solar cells. The improvement in the performance of the solar cell is attributed to the increased internal quantum efficiency, balanced mobility between electrons and holes, and minimized charge recombination.
关键词： interfacial layers,alcohol-soluble polyfluorene,interlayers,organic solar cells,conjugated polyelectrolytes,Carbon nanotubes,electron transport layers,composites
更新于2025-09-23 15:19:57
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Prolonged Lifetime in Nanocrystal Light-Emitting Diodes Incorporating MoS <sub/>2</sub> -Based Conjugated Polyelectrolyte Interfacial Layer as an Alternative to PEDOT:PSS
摘要： Colloidal semiconductor nanocrystals (NCs), and recently nanoplatelets (NPLs), owing to their efficient and narrowband luminescence, are considered as frontier materials for the light-emitting diode (LED) technology. NC-LEDs typically incorporate interfacial layers as charge regulators to ensure charge balancing and high performance. In this communication, we show the prolongation of the lifetime of multilayer solution-processed NC-LEDs by combining a self-doped conductive conjugated polyelectrolyte and exfoliated molybdenum disulfide (MoS2) flakes as an alternative to PEDOT:PSS. The ink features a neutral pH and a tunable hydrophobicity that mainly results in a remarkable stability of LEDs, using CdSe/CdZnS NPLs.
关键词： di-chalcogenides,colloidal nanoplatelets,interfacial layers,light-emitting devices,conjugated polyelectrolytes
更新于2025-09-23 15:19:57
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Water-Processed Organic Solar Cells with Open-Circuit Voltages Exceeding 1.3V
摘要： Conjugated polyelectrolytes are commonly employed as interlayers to modify organic solar cell (OSC) electrode work functions but their use as an electron donor in water-processed OSC active layers has barely been investigated. Here, we demonstrate that poly[3-(6’-N,N,N-trimethyl ammonium)-hexylthiophene] bromide (P3HTN) can be employed as an electron donor combined with a water-soluble fullerene (PEG-C60) into eco-friendly active layers deposited from aqueous solutions. Spin-coating a poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) layer prior to the P3HTN:PEG-C60 active layer deposition considerably increases the open-circuit voltage (Voc) of the OSCs to values above 1.3 V. Along with this enhanced Voc, the OSCs fabricated with the PEDOT:PSS interlayers exhibit 10-fold and 5-fold increases in short-circuit current density (Jsc) with respect to those employing bare indium tin oxide (ITO) and molybdenum trioxide coated ITO anodes, respectively. These findings suggest that the enhanced Jsc and Voc in the water-processed OSCs using the PEDOT:PSS interlayer cannot be solely ascribed to a better hole collection but rather to ion exchanges taking place between PEDOT:PSS and P3HTN. We investigate the optoelectronic properties of the newly formed polyelectrolytes using absorption and photoelectron spectroscopy combined with hole transport measurements to elucidate the enhanced photovoltaic parameters obtained in the OSCs prepared with PEDOT:PSS and P3HTN.
关键词： frontier orbitals,organic semiconductors,organic solar cells,conjugated polyelectrolytes,sustainable fabrication
更新于2025-09-23 15:19:57
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Organic-inorganic hybrid composites as an electron injection layer in highly efficient inverted green-emitting polymer LEDs
摘要： Organic-inorganic hybrid light emitting diodes (HyLEDs) consist of an organic emission layer in combination with at least one metal oxide charge injection layer in an inverted structure. Low temperature, solution processing of metal oxide charge injection layers is one of the key factors in reducing the manufacture cost of HyLEDs. Herein, we report the use of composite materials, comprising conjugated polyelectrolytes (CPE) and zinc oxide nanoparticles (ZnO NPs), as the electron injection layer (EIL) in highly-efficient, green-light-emitting poly(9,9-dioctylfluorene-co-benzothiadiazole) (F8BT) polymer LEDs that are carefully optimised for use in an inverted HyLED architecture for the first time. The composite CPE:ZnO EILs are processed via a room temperature, one-step, solution deposition and enable superior device performance relative to ZnO NPs on their own. We find that specifically, they (i) improve EIL morphology, reducing surface roughness as well as pin-hole size and density, (ii) induce a favourable vacuum level shift for electron injection by coordinate bonding between the CPE and ZnO constituents, and (iii) reduce interfacial quenching by passivation of ZnO chemical defects caused by oxygen vacancies. This work is also the first demonstration that blending ZnO NPs and CPE supports much faster electroluminescence turn-on times (~7.12 μs) than for traditional ZnO/CPE bilayer devices (~0.4 s) via ‘locking’ of the CPE mobile ions, as well as higher device performance. This demonstrates good suitability for display applications. After optimisation of the EIL composition and the thickness of the F8BT emissive layer, we achieve promising device efficiencies of 16.5 cd/A and 5.41 lm/W for devices with a 1.1 μm thick F8BT layer, which is particularly relevant for potential roll-to-roll fabrication. These results clearly demonstrate the potential that this organic-inorganic composite EIL material has for the realisation of cheap, scalable and highly efficient, printable HyLED devices.
关键词： inverted,Hybrid light-emitting diodes,nanoparticles,electron injection layers,conjugated polyelectrolytes,zinc oxide
更新于2025-09-19 17:13:59
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Layer-by-layer adsorption: Factors affecting the choice of substrates and polymers
摘要： The electrostatic layer-by-layer technique for fabrication of multi-layered structures of various sizes and shapes using flat and colloidal templates coupled with polyelectrolyte layer-forming materials has attracted significant interest among both academic and industrial researchers due to its versatility and relative simplicity of the procedures involved in its execution. Fabrication of the multi-layered structures using the electrostatic layer-by-layer method involves several distinct stages each of which holds great importance when considering the production of a high-quality product. These stages include selection of materials (both template and a pair of construction polyelectrolytes), adsorption of the first polyelectrolyte layer onto the selected templates, formation of the second layer comprised of the oppositely charged polyelectrolyte and guided by the interactions between the two chosen polyelectrolytes, and multi-layering, where a selected number of layers are produced, and which is conditioned by both intrinsic properties of the involved construction materials and external fabrication conditions such as temperature, pH and ionic strength. The current review summarises the most important aspects of each stage mentioned above and gives examples of the materials suitable for utilization of the technique and describes the underlying physics involved.
关键词： polyelectrolytes,electrostatic layer-by-layer,multi-layered structures,colloidal templates,fabrication conditions
更新于2025-09-10 09:29:36
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Comparative activity of aqueous dispersions of CdS nanocrystals stabilized by cationic and anionic polyelectrolytes in photocatalytic hydrogen production from water
摘要： The results of a study on the photocatalytic activity of aqueous dispersions of Ni-doped CdS nanocrystals (NCs) covered with an amphiphilic polyelectrolyte (PE) shell, i.e., a polycation (NC-PC) or polyanion (NC-PA), are presented for the first time. The H2 evolution rate measured under identical conditions served as a measure of activity. The NC-PC and NC-PA samples were characterized by similar PE content (~40%) and monomodal size distribution. According to our calculations based on the NC dimensions and lattice parameters, about one macromolecule of the PE is required to stabilize one NC. The average hydrodynamic diameter of the NC-PC was found to be 1.5 times larger than that of the NC-PA due to the difference between their chemical structures and different abilities of ionogenic groups to dissociate. The photocatalytic activity of the PE-stabilized CdS nanocrystals was significantly influenced by the type of the PE, while the H2 evolution rate depended on the reducing medium used during the process. When the medium contained Na2S or when the PE-stabilized NCs were pre-treated with Na2S, the effect of the shell type was more pronounced and the activity of NC-PA was 2 to 14 times higher than that of NC-PC.
关键词： polyelectrolytes,nanocrystals,photocatalysis,cadmium sulfide,hydrogen evolution reactions,nickel
更新于2025-09-10 09:29:36
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Thin Film Processes - Artifacts on Surface Phenomena and Technological Facets || Layer-by-Layer Thin Films and Coatings Containing Metal Nanoparticles in Catalysis
摘要： The layer-by-layer (LbL) technique is one of the most promising ways of fabricating multilayer thin films and coatings with precisely controlled composition, thickness, and architecture on a nanometer scale. This chapter considers the multilayer thin films and coatings containing metal nanoparticles. The main attention was paid to LbL films containing metal nanoparticles assembled by convenient methods based on the different intermolecular interactions, such as hydrogen bonding, charge transfer interaction, molecular recognition, coordination interactions, as driving force for the multilayer buildup. Much attention has paid to the LbL films containing metal nanocomposites for multifunctional catalytic applications, in particular, photocatalysis, thermal catalysis, and electrocatalysis. The preparation protocol of LbL-assembled multilayer thin films containing metal nanoparticles (such as Au, Ag, Pd, Pt), metal oxides (Fe3O4), and sulfides (CdS) that are supported on the various surfaces of nanotubes of TiO2, Al2O3 membranes, graphene nanosheets, graphene oxide and further applications as catalysts with respect to photocatalytic, electrocatalytic performances is discussed. The systematization and analysis of literature data on synthesis, characterization, and application of multilayer thin films and coatings containing metal nanoparticles on the diverse supports may open new directions and perspectives in this unique and exciting subject.
关键词： semiconductors,metal nanoparticles,polyelectrolytes,layer-by-layer assembling,thin films and coatings,immobilization,catalysts
更新于2025-09-04 15:30:14