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[Display omitted] • A conjugated polyelectrolyte, PhH-1T, was adopted as a chemical dopant. • PhH-1T provided efficient chemical doping and blend in conjugated polymers. • PhH-1T-doped P3HT organic field-effect transistors improved charge mobility. • Importance of backbone within polymeric dopant for doping was demonstrated. The introduction of extrinsic materials into host materials has been extensively considered for resolving the challenge of intrinsically low charge movement within semiconducting polymers. One of the difficult issues is developing a dopant that can provide a sufficient interfacial area between host and dopant as well as maintain an efficient charge transport pathway without significantly altering the morphological and crystalline properties of semiconducting polymers. Herein, we propose the use of conjugated polyelectrolyte (CPE), a new highly mixable and mutual dopant for achieving enhanced charge mobility in host conjugated polymers. We found that CPE has more homogeneous dispersion in host polymers than non-conjugated polymeric dopants. This results in enhanced charge mobility in the organic field-effect transistor (OFET) based on a novel p-type semiconducting polymer, poly(3-hexylthiophene) (P3HT) (from 0.076 to 0.135 cm2 V−1 s−1). Atomic force microscopy and grazing incident X-ray diffraction measurements were used to confirm the non-destructive behavior of CPE within P3HT. Therefore, it is believed that CPE is promising for use as a homogeneous chemical dopant for polymer semiconductors. [ABSTRACT FROM AUTHOR]

A new photo-crosslinkable donor polymer, PM6-Br50 facilitates the fabrication of p- PHJ OPDs through LbL deposition of D and A materials overcoming solvent-imposed constraints. The integration of a p- PHJ architecture with a conjugated polyelectrolyte as a hole-transport layer resulted in a significantly reduced dark current, leading to a remarkably high specific detectivity. [Display omitted] • A new polymer donor is synthesized by introduction of photo-crosslinkable side chains. • Layer-by-layer OPDs are fabricated utilizing a photo-crosslinkable polymer donor. • A conjugated polyelectrolyte-based HTL is employed to inhibit electron injection. • A significantly high detectivity is achieved with a suppressed dark current. The effective reduction of dark (or noise) current presents a significant hurdle in enhancing the detectivity of organic photodetectors (OPDs). To address this challenge, a photo-crosslinkable donor polymer, PM6-Br50, is synthesized by introducing bromoalkyl side-chains onto the PM6 structure. This modification enables the formation of a pseudo planar heterojunction (p- PHJ) structure of crosslinked donor/acceptor through a layer-by-layer (LbL) sequential process without the necessity for an semi-orthogonal solvent. This innovation effectively overcomes solvent-related limitations in the LbL process. Additionally, we replace the semi-metallic hole-transport layer (HTL), PEDOT:PSS, with a semiconducting conjugated polyelectrolyte (TPAFS-TMA) with a high conduction band. The p- PHJ configuration, featuring pure donor/anode and pure acceptor/cathode contacts, enhances the charge injection barrier for electrons (holes) from the anode (cathode) in the dark under reverse bias, effectively minimizing dark current. Furthermore, the TPAFS-TMA HTL serves to impede electron injection from the anode. Through the synergistic combination of these two strategies, a significantly reduced dark current density (4.03 × 10−10 A cm−2) is measured by four orders of magnitude, compared to the bulk heterojunction OPDs with PEDOT:PSS. Furthermore, we measure remarkably high shot noise-based and total noise current-based specific detectivities of 4.27 × 1013 and 6.97 × 1012 cm Hz1/2 W−1 (with linear dynamic range of 73.7 dB), respectively. [ABSTRACT FROM AUTHOR]

Abstract A platinum(II)-acetylide-based conjugated polyelectrolyte has been designed and synthesized by using polyfluorenes as an O 2 -insensitive fluorophore and Pt(II) complex as an O 2 -sensitive phosphor, which can generate conjugated polyelectrolyte nanoparticle (CPE-nanoparticle) in the aqueous solution owing to their amphiphilic structures. The CPE-nanoparticle displays good sensitivity to O 2 concentration and can detect oxygen levels reversibly. The intracellular ratiometric O 2 sensing performance of the CPE-nanoparticle has been demonstrated by the remarkable variation in the I green / I blue ratio values (0.18–0.85) in HeLa cells under different O 2 levels. Furthermore, O 2 level detection was carried out through time-resolved luminescence imaging (TRLI) to demonstrate the accuracy of the probe based on the CPE-nanoparticle. The CPE-nanoparticle shows a high phosphorescence quantum yield (19.98%) and oxygen quenching efficiency (0.975), which are superior to the existing O 2 probe. The CPE-nanoparticle has been successfully applied in photoluminescence lifetime imaging and time-gated luminescence imaging for monitoring intracellular O 2 levels. Graphical abstract We have designed and synthesized a platinum(II)-acetylide-based conjugated polyelectrolyte, which can generate conjugated polyelectrolyte dots (CPE-Pdots) in water owing to their amphiphilic structures. The CPE-Pdots have been successfully applied in photoluminescence lifetime imaging and time-gated luminescence imaging for monitoring intracellular O 2 concentrations. Image 1 Highlights • A platinum(II)-acetylide based conjugated polyelectrolyte nanoparticle (CPE-nanoparticle) have been prepared. • The intracellular ratiometric O 2 sensing performance of the CPE-Pdots has been demonstrated by the remarkable variation in the I green /I blue ratio values in HeLa cells under different O 2 levels. • The CPE-Pdots have been successfully applied in photoluminescence lifetime imaging and time-gated luminescence imaging for monitoring intracellular O 2 levels, which will remarkably improve the accuracy. [ABSTRACT FROM AUTHOR]

The control of the optoelectronic properties of the interlayers of perovskite solar cells (PSCs) is crucial for achieving high photovoltaic performances. Of the solution-processable interlayer candidates, NiO x is considered one of the best inorganic hole-transporting layer (HTL) materials. However, the power conversion efficiencies (PCEs) of NiO x -based PSCs are limited by the unfavorable contact between perovskite layers and NiO x HTLs, the high density of surface trap sites, and the inefficient charge extraction from perovskite photoactive layers to anodes. Here, we introduce a new organic-inorganic double HTL consisting of a Cu:NiO x thin film passivated by a conjugated polyelectrolyte (PhNa-1T) film. This double HTL has a significantly lower pinhole density and forms better contact with perovskite films, which results in enhanced charge extraction. As a result, the PCEs of PSCs fabricated with the double HTL are impressively improved up to 17.0%, which is more than 25% higher than that of the corresponding PSC with a Cu:NiO x HTL. Moreover, PSCs with the double HTLs exhibit similar stabilities under ambient conditions to devices using inorganic Cu:NiO x . Therefore, this organic-inorganic double HTL is a promising interlayer material for high performance PSCs with high air stability. [ABSTRACT FROM AUTHOR]

To achieve highly efficient organic photovoltaic (OPV) devices, the interface between the photoactive layer and the electrode must be modified to afford the appropriate alignment of the energy levels and to ensure efficient charge extraction at the same time as suppressing charge recombination and accumulation. Recently, p -type conjugated polyelectrolytes (CPEs) have emerged as new hole-transporting materials that can be deposited on electrodes through simple solution processes without additional heat treatment. However, the applications of CPEs have been limited so far because the high electron richness of their conjugated backbones result in low work functions, ∼5.0 eV. Here, by inserting a donor−acceptor (D−A) building block into the CPE backbone, we successfully synthesized a new p -type CPE (PhNa-DTBT), which shows a deep work function above 5.3 eV on several electrodes including Au, Ag, and indium tin oxide. More importantly, PhNa-DTBT produces stable polarons on the polymer backbone and thus achieves a high electrical conductivity of 5.7 × 10 −4 S cm −1 . As a result, an OPV incorporating PhNa-DTBT as a hole-transporting layer was found to exhibit a high performance with a power conversion efficiency of 9.29%. Also, the OPV device shows improved stability in air due to the neutral characteristics of the CPE which is favorable for stabilizing neighbored active and electrode layers. [ABSTRACT FROM AUTHOR]

We report vacuum-free transfer-printing of silver nanowire (AgNW) network film as a top electrode of polymer light-emitting diodes (PLEDs) using conjugated polyelectrolyte (CPE) interfacial layer. AgNW network is delivered from a donor substrate to the desired area of the devices through an elastomeric polydimethylsiloxane (PDMS) mold stamp. The application of CPE layer with an appropriate thickness on the surface of AgNW and light-emitting polymer (LEP) films provides not only good adhesion between the organic and metal layers but also lowering of the work-function of AgNW electrode for better electron injection at LEP/AgNW interface. PLEDs with laminated AgNW top electrode at the optimized condition show the maximum device efficiencies of 3.81 cd A −1 and 2.99 lm W −1 at 4 V, which are comparable to those of PLEDs with Al cathode. [ABSTRACT FROM AUTHOR]

A new ratiometric nanosensor is developed for selective and ultrasensitive detection of melamine based on conjugated polyelectrolyte (CPE)-stabilized silver nanoparticles (P1-AgNPs) by perfectly combining the advantages of CPE and AgNPs. P1 featuring a π -delocalized backbone bearing pyridinyl groups can act as an excellent dual-emission fluorescent probe as well as a polymer localizer for AgNPs. In the presence of melamine, the fluorescence intensity at 386 nm increases owing to the turn-on of the fluorescence of P1, whereas FL intensity at 488 nm decreases due to the melamine-induced aggregation and subsequent aggregation-enhanced emission quenching of P1-AgNPs, therefore leading to the ratiometric fluorescent sensing of analyte. Moreover, analyte-induced aggregation of P1-AgNPs also allows the ratiometric colorimetric measurement of melamine. Under the optimum conditions, this facile ratiometric nanosensor favors the fluorescent and colorimetric determination of melamine in liquid milk products with the detection limit as low as 0.1 and 0.45 nM, respectively. [ABSTRACT FROM AUTHOR]

A new conjugated polyelectrolyte material, namely, poly [9,9-bis((6′- N , N , N -trimethylamino)hexyl)-fluorene- alt - co -benzoxadiazole dibromide] (PFBD) is reported as electron transport layer (ETL) in polymer solar cells. We observed a light-soaking effect and described how a pre-UV light treatment on PFBD ETL is essential for attaining higher efficiencies (>7%) and negate the light-soaking problem. The pre-UV light treatment on PFBD layer is found to directly influence its molecular structure and result in reduction of the work function and increased electron mobility in PFBD which corroborates well with the observed lower series resistances obtained from dark current analysis and impedance spectra, and therefore enhancement in open-circuit voltage and fill factor. Moreover, after the pre-UV light treatment, the maximal efficiency of the solar cells retains at a nearly similar level for at least 26 days. [ABSTRACT FROM AUTHOR]

We investigate hybrid tandem solar cells that rely on the combination of solution-processed depleted-heterojunction colloidal quantum dot (CQD) and bulk heterojunction polymer:fullerene subcells. The hybrid tandem solar cell is monolithically integrated and electrically connected in series with a suitable p–n recombination layer that includes metal oxides and a conjugated polyelectrolyte. We discuss the monolithic integration of the subcells, taking into account solvent interactions with underlayers and associated constraints on the tandem architecture, and show that an adequate device configuration consists of a low bandgap CQD bottom cell and a high bandgap polymer:fullerene top cell. Once we optimize the recombination layer and individual subcells, the hybrid tandem device reaches a V OC of 1.3 V, approaching the sum of the individual subcell voltages. An impressive fill factor of 70% is achieved, further confirming that the subcells are efficiently connected via an appropriate recombination layer. [ABSTRACT FROM AUTHOR]

A new sensing system is developed for selective and ultrasensitive detection of iodide based on the inner filter effect (IFE) between conjugated polyelectrolyte-stabilized silver nanoparticles (P1–AgNPs) and 4-oxo-4-(pyren-1-ylmethoxy) butanoic acid ( probe 1 ). P1–AgNPs are designed to be capable of functioning as a composite light-absorber. Meanwhile, probe 1 is selected as an ideal fluorophore because its emission spectrum can perfectly overlap with the absorption band of P1–AgNPs. The intense fluorescence of probe 1 quenched by P1–AgNPs can be efficiently recovered after adding H 2 O 2 and I − via the oxidation-etching and regeneration of P1–AgNPs. Under the optimum conditions, this facile IFE-based approach allows the sensitive and selective determination of I − in tap water, iodized salt and urine with the detection limit as low as 0.3 nM ( S / N =3). Interestingly, the regenerated AgNPs is in smaller size and well-dispersed perhaps due to the particular role of P1 as a polymer localizer containing pyridinyl and sulfonate groups. [ABSTRACT FROM AUTHOR]

[Display omitted] • Environmentally friendly Pb-free QPDs were reported by utilizing AgBiS 2 NCs. • A novel CPE increased D* of QPDs by 3–4.5 times higher than that without CPE. • The ultrafast response time of 1.0 μs were achieved under 680 nm red light. • The promising D * of 1.4 × 1012 Jones at −0.5 V was achieved under 680 nm light. • The highest D * values and fastest response time were reported among the AgBiS 2 QPDs. Lead-free quantum-dot photodetectors (QPDs) are currently the subject of research interest due to the environmental threat posed by lead, but relatively poor photodetection ability has been reported so far. Here, we develop high-performance AgBiS 2 nanocrystal (NC)-based QPDs with a responsivity (R) of 0.55 A/W and detectivity (D*) of 1.4 × 1012 Jones at −0.5 V under a 680 nm LED light (1.0 mW/cm2) by incorporating a novel conjugated polyelectrolyte (CPE) as a cathode buffer layer (CBL) on the surface of the electron transporting layer (ETL). The CPE was developed by co-polymerization of bromohexyl-substituted fluorene and pyrene rings, followed by quaternization with trimethylamine at the terminal alkyl chains. The synthesized CPE decreased the work function and reduced the number of trap sites at the ETL surface, which increased photocurrent density and reduced dark current density, resulting in a D* value by 3 to 4.5 times greater than that without CPE treatment. Our AgBiS 2 NC-based QPDs achieved ultrafast rising and falling response times of 1.0 and 3.2 μs, respectively, under the 680 nm LED light, and the CBL layer was able to rapidly remove residual current density in the off-light state, improving the dynamic characteristics of AgBiS 2 QPDs under near-infrared light (940 nm). [ABSTRACT FROM AUTHOR]

Highlights: [•] PTPE x F y N were synthesized and showed AIEE or DCFR characteristic. [•] AIEE mechanism was due to k f has almost no change while k nr decreases. [•] Quantification of heparin using PTPE 0.2 F 0.8 N shows linearity and sensitivity. [ABSTRACT FROM AUTHOR]

Highlights: [•] We investigated the effects of side chain functionality and length on organic memory. [•] WPFs showed reliable non-volatile characteristics and good device-to-device uniformity. [•] WPFs with the EO side chains showed better memory characteristics than those of the alkyl side chains. [•] As the EO unit lengthened, the ON/OFF ratio of the memory device gradually increased. [•] As the EO unit lengthened, the threshold voltages progressively decreased. [Copyright &y& Elsevier]

Abstract: Detailed optimization of the device architecture of bulk heterojunction organic solar cells is of crucial importance when eventually targeting commercial applications. It has been shown before that the efficiency of such devices can be increased significantly upon incorporation of an imidazolium-substituted polythiophene interlayer. The cause of this increase in efficiency was, however, still unclear and is investigated here by a combination of PeakForce Quantitative Nanomechanical Mapping, PeakForce TUNA and Kelvin Probe Force Microscopy. A link between the local morphological and electrical properties is established. We show that the conjugated polyelectrolyte interlayer acts as a hole blocking layer. Additionally, illuminated Kelvin Probe Force Microscopy indicates that the interlayer creates an extra built-in electric field promoting charge transfer from the bulk heterojunction active layer into the interlayer. [Copyright &y& Elsevier]

Highlights: [•] A hydrophilic conjugated polyfluorene was synthesized and utilized as cathode interlayer. [•] The influence of fine tuning the polymer backbone structures has been investigated. [•] The resulting polyfluorene cathode interlayers demonstrated backbone dependent performance. [•] For PLEDs there is a 90% increase in luminous efficiency relative to Ca/Al for PPFN-OH/Al cathode. [•] For PSCs there is a 19% increase in PCE relative to Ca/Al for ITO/PPFN-OH electron extraction electrodes. [Copyright &y& Elsevier]

Highlights: [•] Cs2CO3:conjugated polyelectrolyte blended interfacial layer is used. [•] Improved electron injection from Ag electrode is achieved. [•] Solution-processed Ag cathode is fabricated using Ag nano-ink. [•] Interfacial layer prevents Ag nano-ink from penetrating into emissive layer. [•] Solution-processed device using Ag nano-ink exhibits luminance (10,000cd/m2). [Copyright &y& Elsevier]

Abstract: The work-function of indium tin oxide (ITO) electrodes was tuned with an interfacial dipole layer (WPF-oxy-F) to reverse the polarity in polymer solar cells (PSCs) with an inverted structure. The photoactive layer was based on poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). Silver (Ag) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) were used as the top anode. The optimized conditions for the fabricated I-PSCs included an open-circuit voltage (V oc) of 0.68V, a fill factor (FF) of 64%, and a power conversion efficiency (PCE) of 3.86% through post-annealing at 170°C. The high performance of I-PSC is due partly to the improved interfacial contact at active/PEDOT:PSS and mainly to the increase of the work-function of annealed PEDOT:PSS/Ag at 170°C for 30min. Here, we investigated the effect of post-annealing on I-PSC devices by carrying out various annealing sequences. [Copyright &y& Elsevier]

Abstract: Inverted polymer:fullerene solar cells are reported using the conjugated polyelectrolyte poly(3-[6-(N-methylimidazolium)hexyl]thiophene) bromide P3ImHT as ultra-thin cathode interlayer to reduce the work-function (WF) of ITO for improved electron selectivity. Similar to ITO/TiO x cathodes, UV exposure is found necessary in the case of ITO/CPE to achieve a high fill factor on the order of 60%. UV illumination is shown to lead to a reduction of the ITO WF which in combination with WF lowering due to the dipole of the CPE leads to a suitable electron selective cathode. As a result, inverted solar cells with an efficiency of 4.8% are achieved. This is the highest efficiency of an inverted OSC using a conjugated polyelectrolyte as interface modifier directly on top of ITO. [Copyright &y& Elsevier]

Abstract: The preparation of cellulose acetate-poly-(9,9-bis(6′-N,N,N-trimethylammonium)-hexyl-fluorene phenylene) bromide (HTMA-PFP) blend films by solvent casting from a dispersion is reported. Films were characterized by UV–visible spectroscopy, SEM, electrical conductivity, TGA and DSC. It was found that morphological and physical chemical properties of blends were dependent both on the solvent and the degree of polymerization of cellulose acetate. The fluorescence properties of different blends were evaluated by fluorescence microscopy and it was shown that they are dependent on the structural properties of the blend as well as the aggregation level of the polyfluorene. Release kinetics of HTMA-PFP, incorporated into blend films, in SDS aqueous solutions have been studied and are discussed on the basis of the Korsmeyer–Peppas equation. [Copyright &y& Elsevier]

Abstract: We report here a label-free method for ultrasensitive and selective assay of protease activity based on the peptide-induced fluorescence quenching of conjugated polyelectrolyte (PPESO3). It is very interesting to find that there is a critical length of oligo-polyarginine (i.e., Arg5) below which 1) the quenching efficiency of PPESO3 is sharply decreased, and more importantly, 2) the trypsin-catalyzed hydrolysis is greatly slowed down. This opens good opportunities for not only the ultrasensitive assay of trypsin, but the specific detection of other proteases if carefully designing an appropriate peptide length and the cleavage site. Herein, the enzyme selected as a proof of concept is chymotrypsin. Due to the essence that any cleavage of the designed peptide probes will result in a notable decrease or even a complete loss of their capability to quench the emission of PPESO3, the limits of detection for trypsin and chymotrypsin have been found as low as 0.25ng/mL (11pM) and 0.15ng/mL (6pM), respectively. Both are superior to those of most previous methods by 1–2 orders or higher. [Copyright &y& Elsevier]

Abstract: This review deals with the emerging field of fluorescent conjugated polymers for the development of chemical and/or biochemical sensors. As a result of their amplified physical properties due to a “molecular wire effect”, these materials offer excellent characteristics to develop different sensing schemes (e.g., employing direct superquenching or relying on development of fluorescence-resonance-energy-transfer formats). The versatility of their synthesis procedures allows us to introduce the desired functional groups to achieve analytically useful interactions with analytes [e.g., from transition-metal ions to explosives, or even, in recent years, relevant biomolecules (e.g., proteins or DNA, where conformational changes play a decisive role in detection)]. [Copyright &y& Elsevier]

Abstract: This review focuses on novel fluorescent sensing systems for rapid, sensitive, reliable and cost-effective DNA detection in clinical diagnostics. Several materials, including conjugated polyelectrolytes, nanomaterials and molecular beacons, which exhibit attractive properties, are involved to stabilize and to amplify the signal. We describe and evaluate these different DNA analytical methods and give some pointers as to the likely directions of future developments. [Copyright &y& Elsevier]

Abstract: In recent years, conjugated polyelectrolytes (CPEs) that feature good water-solubility have drawn great attention as optical transducers in high sensitive bio- and chemo-sensors due to their predominant optical/electronic properties and remarkable signal amplification. Herein, a sensitive and selective assay for nitrite ion has successfully been developed based on the fluorescence superquenching of an anionic CPE, PPESO3. With the sensor format composed of PPESO3 and H+, Fe2+ can easily be oxidized into Fe3+ in the presence of NO2 −, and the later dramatically quenches the fluorescence of PPESO3. Indeed, the inclusion of conjugated polyelectrolyte into the sensory scheme can give rise to a notable enhancement of fluorescence response, which endows the newly proposed NO2 − probe with high sensitivity. Thus, nitrite ion within a relatively wide concentration range (0–70μM) can be determined in a rather simple and sensitive manner with a detection limit of 0.62μM (∼28ppb). Additionally, most other anions such as halogen ions, acetate, sulfate, carbonate, phosphate and even nitrate, show minor interference on the NO2 − detection. [Copyright &y& Elsevier]

Abstract: Conjugated polyelectrolytes (CPEs) have become one of the most utilized materials in chemo- and bio-sensory systems. Useful properties of CPEs, such as amplified quenching effects and aggregation behavior, are illustrated in detail in order to provide guidelines for underlying concepts of CPE-based sensors. Well established sensing mechanisms, such as conformational changes and fluorescence resonance energy transfer, are reviewed with representative examples. Target species include small ions, small biomolecules, proteins, enzymatic activities, and DNA. New and unique mechanisms for CPE-based sensing are also described. [Copyright &y& Elsevier]

Abstract: The conjugated polyelectrolyte (CPE) poly{9,9′-bis[6″-(N,N,N-trimethylammonium)-hexylfluorene-alt-co-phenylene] dibromide} (PFPN+Br−) demonstrates a high solubility in methanol in comparison to other more hydrophilic or hydrophobic solvents. We have employed a combination of pulsed-field-gradient-NMR, photoluminescence (PL), and Raman spectroscopy to establish the conformation and aggregation behavior of PFPN+Br− in methanol, with the aim to attain information on how to design CPEs with a high solubility in a preferred solvent. We find that the diffusion coefficient and PL spectrum of PFPN+Br−, as well as the Raman-active methyl rocking mode of methanol, all exhibit a strong dependence on PFPN+Br− concentration. We rationalize our findings with a model in which PFPN+Br− forms aggregates via π–π interactions between main-chain segments, while the ionic side chains are surrounded and electrostatically screened by the methanol solvent. Accordingly, the notably high solubility of PFPN+Br− in methanol is rationalized by favorable interactions between the ionic side chains and the methanol molecules. We propose that an appropriate design of a high-solubility CPE should consider a matching of the mixed hydrophobic/hydrophilic character of the ionic side chain with that of the preferred solvent. [Copyright &y& Elsevier]

Emulating synaptic bionics and plasticity is considered to be the first step in obtaining efficient brain-like artificial neural networks. The electrical properties of organic polymeric materials can be tailored through chemical structure design and synthesis; therefore, memristive devices based on organic polymer materials have unique advantages for neurosynaptic biomimetic applications. In this work, a metalloporphyrin was introduced into the main chain of a polymer through Suzuki coupling, and a novel polyfluorene-based conjugated polyelectrolyte, PFI-ZnPor, was synthesized. The conjugated polyelectrolyte displayed good thermal stability and was highly soluble in polar solvents. Memristive devices with an Al/PFI-ZnPor/ITO structure were prepared by the solution spin-coating method. Synaptic biomimetic and synaptic plasticity were successfully simulated by using this device. The synaptic performance of the memristive device originated from the redox behavior of metalloporphyrin and the ion migration of conjugated polyelectrolyte under the electric field. This work provides new insights into the design of organic polymeric memristive materials for neurosynaptic biomimetic devices. A novel polyfluorene-based conjugated polyelectrolyte containing metalloporphyrin was synthesized. Synaptic biomimetic and synaptic plasticity were successfully simulated by using memristive devices with an Al/PFI-ZnPor/ITO structure. [Display omitted] • A novel conjugated polyelectrolyte containing metalloporphyrin was synthesized. • The Al/PFI-ZnPor/ITO electronic device exhibited distinct history-dependent memristive behavior. • Synaptic biomimetic and synaptic plasticity were successfully simulated by using the memristive device. [ABSTRACT FROM AUTHOR]

Abstract: An anionic poly(phenylenevinylene) derivative was prepared by Glich dehydrohalogenation polymerization and characterized by Fourier transformed infrared spectroscopy, UV–vis spectroscopy, photoluminescent spectroscopy and thermogravimetric analysis. The water-soluble conjugated polyelectrolyte was deposited on an interdigitated gold electrode by dip coating, and the humidity sensitive properties of the resulting thin film were investigated at room temperature over the range of 25–98% RH. It was found that the polymer exhibited a high conductivity even without doping, and its impedance response to humidity showed a sigmoidal shape. The polymer doped with LiClO4 and LiCl showed high humidity sensitivity, but their humidity responses were different. For comparison, the humidity sensitive properties of doped sodium polystyrenesulfonate, which is a typical saturated polyelectrolyte, were also measured. It is proposed that the effect of doping agents on the humidity response of the conjugated polyelectrolyte is related to their interaction with the conjugated backbone. [Copyright &y& Elsevier]

Abstract: MEHPPV precursors containing dithiocarbamate groups along with methoxy units were used to initiate polymerisation of monomers, such as methyl acrylate and t-butyl acrylate, to yield grafted precursor systems. Typically, the grafting was done by UV irradiation, and the molecular weight of the grafted precursor polymer was seen to increase with exposure time. The t-butyl acrylate-grafted precursors were converted to the conjugated MEHPPV derivative by acid-catalysed elimination of the methoxy groups, during which time the hydrolysis of the t-butyl groups also occurred resulting in a hydrophilic MEHPPV with poly(acrylic acid) graft chains. These grafted MEHPPV derivatives were soluble in aqueous base as well as alcohols. Fluorescence spectroscopic studies indicated that these acrylic acid-grafted MEHPPV derivatives were very sensitive to analyte like methyl viologen. [Copyright &y& Elsevier]

Abstract: The optical properties of various conjugated, water-soluble polymers in general, and MPS-PPV [poly (2-methoxy 5-sulfopropoxy) 1,4-phenylene vinylene] in particular, have been found to be useful in the fabrication of sensors for ionic species. We report our investigations on the influence of various ionic species on the fluorescence properties of DPS-PPV, possessing two sulphonate groups per repeating unit. The emission quantum yield of this polymer exceeds that of the mono-sulphonated derivative by a factor of 10, potentially increasing the sensitivity of such sensors. The fluorescence intensity of aqueous DPS-PPV decreases following the addition of certain cations, and some small spectral shifts occur. The origin of these changes will be discussed based on steady state measurements and excited state dynamics. The emission behavior of DPS-PPV adsorbed onto single silica micro spheres is also reported. [Copyright &y& Elsevier]

[Display omitted] • A polyelectrolyte was designed with the same main-chain of a reported polymer HTM. • HTM based on it showed an efficiency of 19.92% in an inverted solar cell. • More thiophene unit gave a superior hole-extraction and defect-passivation ability. Owing to its high wettability and the resulting compatibility with the future industrial device fabrication process, the conjugated polyelectrolyte (CPE) has becoming a promising hole-transporting material (HTM) in the inverted perovskite solar cell (iPSC); however, only a few highly efficient CPEs have been reported probably due to the limited pool of molecular designing strategies. Here we construct a CPE named DTB(Na) with the same main-chain of a polymer DTB(EH) that was previously employed as a dopant-free HTM in a highly efficient regular type PSC (rPSC) and with simple water/alcohol soluble side-chains. Compared with its analog bearing the only variation of less thiophene units in the main-chain, DTB(Na) shows stronger capacities of hole-extraction and defect-passivation, which should be ascribed to the more intensive exposure of thiophene functional unit to the perovskite layer. As a result, the DTB(Na) iPSC device presents enhanced values on all the photovoltaic parameters and long-term stability, and a power conversion efficiency of 19.92% is realized. Our results demonstrate the feasibility for efficient polymeric HTMs in rPSCs and iPSCs to share the same main-chains, thus enriching the molecular designing strategies and probably expanding the library of efficient HTMs for iPSCs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Conjugated polyelectrolyte was developed and used as a dopant in PSCs. • PPNNA doping improves the formation of the perovskite film. • PPNNA doping realizes efficient surface passivation and electron extraction. • PPNNA can significantly enhance device performance and stability. Perovskite solar cells (PSCs) have achieved great success in the past few years because of outstanding photovoltaic performance. However, the existence of electronic trap states in the perovskite film is an obstacle for the fabrication of high-performance and stable PSCs. Herein, a linear conjugated polyelectrolyte was developed and employed as a dopant to improve the performance and stability of the perovskite film. The PPNNA doping can passivate surface defects to reduce the electronic trap states in the perovskite film, while simultaneously enhancing the electron extraction and transport to achieve high-efficiency solar cells. Furthermore, the PPNNA-doped perovskite film shows better stability from efficient surface passivation. The optimal 0.4% PPNNA-doped device exhibits better photovoltaic efficiency (20.38%) with enhanced device stability as compared to the control device (18.51%). This novel method by doping with the conjugated polyelectrolyte provides a pathway to fabricate high-efficiency and stable inverted PSCs. [ABSTRACT FROM AUTHOR]

[Display omitted] The development of novel imaging agents for fluorescence detection of latent fingerprint is still important for criminal investigation and identity recognition. Herein, we reported a simple and robust method to prepare multi-color conjugated polymer micelles for visualization of fingerprints. A conjugated polyelectrolyte, poly[(9,9-bis(3′-((N,N -dimethyl)-N-ethylammonium)-propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN), was dissolved in water forming polymer micelles with blue emission. Green and red emissions were facilely achieved by incorporating small organic fluorophores including coumarin 6 (C6) and Nile red (NR) into the PFN micelles, respectively. These micelles exhibited bright fluorescence both in solution and solid film, where significant aggregation-caused quenching was avoided and fluorescence resonance energy transfer from PFN to C6 or NR was enhanced. Through a simple solution method, these polymer micelles proved their high affinity towards the fingerprint ridges. Accordingly, fluorescent fingerprint images with high-resolution were obtained, which were less interfered by fluorescence background from substrate and overlap between adjacent fingerprints. [ABSTRACT FROM AUTHOR]

• PM was fabricated via chemical grafting of CPE on commercial PVDF. • The surficial hydrophilicity can be controlled by the anion exchange on CPE. • Organic and inorganic pollutants were successfully removed on the PM surface. • The hydrophilic PM showed excellent antimicrobial activity under visible light. • The anti-biofouling property enabled complete flux recovery in repeated cycles. The photocatalytic membrane (PM) is a promising platform to impart membranes with an anti-biofouling property. However, the fabrication of effective PMs remains challenging because the physical loading of photoactive materials on the membrane can cause pore blocking and layer delamination due to repetitive operations. In this study, we demonstrate a chemical grafting of conjugated polyelectrolytes (CPEs) on a PVDF membrane surface to generate visible-light-active PMs with high stability. Using chemical tethering of CPE on the membrane followed by anion exchange, the surficial hydrophilicity of PM is improved significantly without compromising its porosity and water permeability. The hydrophilic PM exhibits excellent performance for photo-degradation of organic dyes, photo-reduction of Cr(VI), and photocatalytic inactivation of mixed-culture biofilm under visible light irradiation. The anti-biofouling property enables > 97 % flux recovery in repeated filtration cycles through the visible light treatment, even after it is fouled with a super-saturated bacterial feed solution (109 CFU/mL). [ABSTRACT FROM AUTHOR]

• The mixture of PCBM:PFN facilitates the film formation on the surface of 2D perovskite. • Involving PFN in PCBM can improve the electron extraction property for ETL. • Electrical conductivity of ETL is increased by mixing PFN in PCBM. • Long-term stability of 2D perovskite devices are enhanced with PCBM:PFN as ETL. We introduce a facile method to form a well-deposited [6,6] -phenyl-C 61 -butyric acid methyl ester (PCBM) film on the surface of 2D perovskite by mixing the poly[(9,9-bis(3′-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9–dioctylfluorene)] (PFN), which can benefit the film formation of PCBM as well as improve the electron extraction efficiency of electron transport layer (ETL). As a result, the optimized group presents an enhanced photovoltaic performance with power conversion efficiency of 12.7%, which is attributed to the improved interfacial contact and better matched energy alignment. It is observed that the fully covered and dense ETL (PCBM:PFN) leads to a better environmental stability of devices in ambient air condition without encapsulation. [ABSTRACT FROM AUTHOR]

Conjugated polyelectrolytes (CPEs) have been widely used as reporters in colorimetric assays targeting nucleic acids. CPEs provide naked eye detection possibility by their superior optical properties however, as concentration of target analytes decrease, trace amounts of nucleic acid typically yield colorimetric responses that are not readily perceivable by naked eye. Herein, we report a pixelated analysis approach for correlating colorimetric responses of CPE with nucleic acid concentrations down to 1 nM, in plasma samples, utilizing a smart phone with an algorithm that can perform analytical testing and data processing. The detection strategy employed relies on conformational transitions between single stranded nucleic acid-cationic CPE duplexes and double stranded nucleic acid-CPE triplexes that yield distinct colorimetric responses for enabling naked eye detection of nucleic acids. Cationic poly[N,N,N-triethyl-3-((4-methylthiophen-3-yl)oxy)propan-1-aminium bromide] is utilized as the CPE reporter deposited on a polyvinylidene fluoride (PVDF) membrane for nucleic acid assay. A smart phone application is developed to capture and digitize the colorimetric response of the individual pixels of the digital images of CPE on the PVDF membrane, followed by an analysis using the algorithm. The proposed pixelated approach enables precise quantification of nucleic acid assay concentrations, thereby eliminating the margin of error involved in conventional methodologies adopted for interpretation of colorimetric responses, for instance, RGB analysis. The obtained results illustrate that a ubiquitous smart phone could be utilized for point of care colorimetric nucleic acids assays in complex matrices without requiring sophisticated software or instrumentation. Image 1 • A cost effective sensory cartridge and an algorithm compatible with smart phone are developed. • Conjugated polyelectrolyte impregnated paper for detection of nucleic acid. • A pixelated assay to visualize nucleic acid down to concentration of 1 nM. [ABSTRACT FROM AUTHOR]

Conjugated polyelectrolyte based on benzotriazole (BT) with tetravalent amine-end side chain and benzothiadiazole (BTz) conjugated alternating repeat units, named PBTBTz-TMAI was initially designed and synthesized. Fullerene- and non-fullerene-based polymer solar cells were fabricated using PBTBTz-TMAI as the cathode interlayer. Consequently, power conversion efficiencies of 8.4% and 10.5% were achieved for the fullerene PTB7:PC 71 BM-based and non-fullerene PBDB-T:ITIC-based single-junction devices, respectively. The enhanced performance is attributed to the appropriate energy level alignment of the active layer with PBTBTz-TMAI and the efficient electron transfer from the active layer to the cathode electrode. Power conversion efficiency of 10.5% was achieved for the non-fullerene PBDB-T:ITIC-based single-junction device with PBTBTz-TMAI interlayer. The enhanced performance is attributed to the appropriate energy level alignment of the active layer with PBTBTz-TMAI and the efficient electron transfer from the active layer to the cathode electrode. Image 1 • 10.5% enhanced efficiency for PBDB-T:ITIC-based device with PBTBTz-TMAI. • Better energy level alignment of active layer with PBTBTz-TMAI. • Efficient electron transfer from active layer to PBTBTz-TMAI. [ABSTRACT FROM AUTHOR]

Abstract: Polymer light-emitting diodes (PLEDs) were prepared using an environment-friendly alcohol-soluble quaternized aminoalkyl-substituted conjugated polyfluorene co-polymerizing 2,1,3-benzothiadiazole monomer (PFNBr-BTDZ05) as an emitter, a high work-function Au metal as a cathode. The device structure used here is indium–tin–oxide (ITO)/poly(N-vinylcarbazole) (PVK)/PFNBr-BTDZ05/Au, where PVK is an anode buffer layer acting as the hole injection. The maximal external quantum and luminance efficiencies of 0.73% and 0.86 cd/A are obtained, and the maximal luminance is nearly 700 cd/m2 at 13 V, which was the highest brightness value reported in PLEDs with the Au metal cathode. This conjugated polyelectrolyte has such excellent electron injection ability that the device with the structure of ITO/poly(ethylene dioxythiophene)/poly(2-(4-(3′,7′-dimethyloctyloxy)-phenyl)-p-phenylenevinylene)/PFNBr-BTDZ05/Al exhibits a high external quantum efficiency of 7.0%. The electron-injecting mechanism of PFNBr-BTDZ05 was discussed. [Copyright &y& Elsevier]

Bioelectrochemical systems (BESs) are emerging as a platform technology with great application potentials such as wastewater remediation and power generation. Materials for electrode/microorganism modification are being examined in order to improve the current production in BESs. Herein, we report that the current production increased almost one fold in single-chamber BES reactors, by adding a conjugated polyelectrolyte (CPE-K) in the growth medium to co-form the anodic biofilm with Geobacter sulfurreducens cells. The CPE-K treated BESs had a maximum current density as high as 12.3 ± 0.5 A/m2, with that of the controls being 6.2 ± 0.7 A/m2. Improved current production was sustained even after CPE-K was no longer added to the medium. It was demonstrated that increased current resulted from improvement of certain biofilm properties. Analysis using electrochemical impedance spectroscopy (EIS) showed that CPE-K addition decreased the charge transfer resistance at the cell/electrode interface and the diffusion resistance through the biofilm. Protein quantification showed increased biomass growth on the electrode surface, and confocal scanning microscopy images revealed enhanced biofilm permeability. These results demonstrated for the first time that conjugated polyelectrolytes could be used for G. sulfurreducens biofilm augmentation to achieve high electricity production through tuning the anodic biofilm in BESs. • Adding CPE-K increased maximum current densities of G. sulfurreducens by one-fold. • The increased current sustained even with no further addition of CPE-K. • The improved performance resulted from increased biomass growth. • Adding CPE-K decreased charge transfer resistance at the cell/electrode interface. • Addition of CPE-K lead to more permeable G. sulfurreducens biofilm structure. [ABSTRACT FROM AUTHOR]