Polyethylene glycol-polyvinylidene fluoride/TiO2 nanocomposite polymer coatings with efficient antifouling strategies: Hydrophilized defensive surface and stable capacitive deionization

Capacitive deionization (CDI) is flourishing as an energy-efficient and cost-effective water desalination method. However, challenges such as electrode degradation and fouling have hindered the practical deployment of CDI technology. To address these challenges, the key point of our strategy is applying a hydrophilic coating composed of polyethylene glycol (PEG)-functionalized nano-TiO2/polyvinylidene fluoride (PVDF) to the electrode interface (labeled as APPT electrode). The PEG/PVDF/TiO2 layer not only mitigates the co-ion depletion, but also imparts the activated carbon (AC) electrode hydrophilicity. As anticipated, the APPT electrode possessed an enhanced desalination capacity of 83.54 μmol g-1 and a low energy consumption of 17.99 Wh m-3 in 10 mM sodium chloride solution compared with the bare AC electrode. Notably, the APPT maintained about 93.19 % of its desalination capacity after 50 consecutive adsorption-desorption cycles in the presence of bovine serum albumin (BSA). During the trial, moreover, no obvious overall performance decline was noted in concentration reduction (Δc), water recovery (WR) and productivity (P) over 50 cycles. This strategy realizes energy-efficient, antifouling and stable brackish water desalination and has great promise for practical applications.

Spatially selective defect management of CsPbI3 films for high-performance carbon-based inorganic perovskite solar cells

Defects formed at the surface, buried interface and grain boundaries (GB) of CsPbI3 perovskite films considerably limit photovoltaic performance. Such defects could be passivated effectively by the most prevalent post modification strategy without compromising the photoelectric properties of perovskite films, but it is still a great challenge to make this strategy comprehensive to different defects spatially distributed throughout the films. Herein, a spatially selective defect management (SSDM) strategy is developed to roundly passivate various defects at different locations within the perovskite film by a facile one-step treatment procedure using a piperazine-1,4-diium tetrafluoroborate (PZD(BF4)2) solution. The small-size PZD2+ cations could penetrate into the film interior and even make it all the way to the buried interface of CsPbI3 perovskite films, while the BF4- anions, with largely different properties from I- anions, mainly anchor on the film surface. Consequently, virtually all the defects at the surface, buried interface and grain boundaries of CsPbI3 perovskite films are effectively healed, leading to significantly improved film quality, enhanced phase stability, optimized energy level alignment and promoted carrier transport. With these films, the fabricated CsPbI3 PSCs based on carbon electrode (C-PSCs) achieve an efficiency of 18.27%, which is among the highest-reported values for inorganic C-PSCs, and stability of 500 h at 85 °C with 65% efficiency maintenance.

Electrically-assisted anaerobic digestion under ammonia stress: Facilitating propionate oxidation and activating methanogenesis via direct interspecies electron transfer

Electrical assistance is an effective strategy for promoting anaerobic digestion (AD) under ammonia stress. However, the underlying mechanism of electrical assistance affecting AD is insufficiently understood. Here, electrical assistance to AD under 5 g N/L ammonia stress was provided, by employing a 0.6 V voltage to the carbon electrodes. The results demonstrated remarkable enhancements in methane production (104.6 %) and the maximal methane production rate (207.7 %). The critical segment facilitated by electro-stimulation was the microbial metabolism of propionate-to-methane, rather than ammonia removal. Proteins in extracellular polymer substances were enriched, boosting microbial resilience to ammonia intrusion. Concurrently, the promoted humic/fulvic-substances amplified the microbial electron transfer capacity. Metagenomics analysis identified the upsurge of propionate oxidation at the anode (by e.g. unclassified_c__Bacteroidia), and the stimulations of acetoclastic and direct interspecies electron transfer-dependent CO2-reducing methanogenesis at the cathode (by e.g. Methanothrix). This study provides novel insights into the effect of electrical assistance on ammonia-stressed AD.

Electrocatalytic barium-oxide decorated MWCNT amperometric sensor for the quantification of anesthetic drug Procaine

Procaine hydrochloride (P.HCl) is one of the earliest and most well-established local anesthetic drugs used in medicine. Though it is employed frequently for effective clinical nerve blocks during surgeries, its immoderate administration has often shown reports of systemic toxicity. To prevent such repercussions, developing a sensor for the drug is crucial to enable real-time monitoring of the drug and assist in quality control procedures during its industrial preparations. Thus, in this work, we have fabricated a simple yet highly selective and sensitive amperometric sensor for P.HCl detection based on a Barium-oxide multi-wall carbon nanotube-modified carbon paste electrode (BaO-MWCNT/CPE). Herein, we have adopted a novel approach devoid of sophisticated procedures and pretreatments for rapidly determining P.HCl. Furthermore, experimental conditions, including supporting electrolytes, pH, and scan rate, were optimized to achieve a well-defined P.HCl anodic peak current at 631 mV, which is lower than the previously reported peak potentials, indicating an advantage of reduced overpotential. Besides, a striking 66-fold rise in current responsiveness to P.HCl was achieved upon modification with BaO-MWCNT. Such an intense signal enhancement upon electrode modification compared to bare CPE was due to the strong electrocatalytic feature of BaO-MWCNT, which was verified using surface morphology studies with scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). Additionally, the charge transfer kinetics analyzed via electrochemical impedance spectroscopy (EIS) justified the enhancement of electrocatalytic activity upon electrode modification. The developed sensor exhibited a remarkable analytical performance over a wide linear dynamic range of 2.0-100.0 µM with a detection limit of 0.14 µM. Moreover, a significant merit of this sensor is its excellent selectivity towards P.HCl even in the presence of various common interferants. Finally, the versatility of the sensor was further validated by implementing it for the trace analysis of urine and blood serum real samples.

Electron-ion conjugation sites co-constructed by defects and heteroatoms assisted carbon electrodes for high-performance aqueous energy storage

Rapid preparation strategies of carbon-based materials with a high power density and energy density are crucial for the large-scale application of carbon materials in energy storage. However, achieving these goals quickly and efficiently remains challenging. Herein, the rapid redox reaction of concentrated H₂SO₄ and sucrose was employed as a means to destroy the perfect carbon lattice to form defects and insert large numbers of heteroatoms into the defects to rapidly form electron-ion conjugated sites of carbon materials at room temperature. Among prepared samples, CS-800-2 showed an excellent electrochemical performance (377.7 F g^-1, 1 A g^-1) and high energy density in 1 M H₂SO₄ electrolyte owing to its large specific surface area and a significant number of electron-ion conjugated sites. Additionally, CS-800-2 exhibited desirable energy storage performance in other aqueous electrolytes containing various metal ions. The theoretical calculation results revealed increased charge density near the carbon lattice defects, and the presence of heteroatoms effectively reduced the adsorption energy of carbon materials toward cations. Accordingly, the constructed "electron-ion" conjugated sites comprising defects and heteroatoms on the super-large surface of carbon-based materials accelerated the pseudo-capacitance reactions on the material surface, thereby greatly enhancing the energy density of carbon-based materials without sacrificing power density. In sum, a fresh theoretical perspective for constructing new carbon-based energy storage materials was provided, promising for future development of high-performance energy storage materials and devices.

Recent trends on electrochemical determination of antibiotic Ciprofloxacin in biological fluids, pharmaceutical formulations, environmental resources and foodstuffs: Direct and indirect approaches

In the last few decades, pharmaceuticals, credited with saving millions of lives, have emerged as a new class of environmental contaminants. These compounds can have both chronic and acute harmful effects on aquatic ecosystems and consequently on human health. Therefore, there is an urgent need for the development of extremely sensitive, portable, and low-cost devices to perform analysis. In the present review article, recent reports on the application of various voltammetric and photo-electrochemical techniques using different electrode materials for the determination of antibiotic Ciprofloxacin (CIPRO) are reported. This review provides an insight into direct and indirect electrochemical approaches as well as the photoelectrochemical methods used for the determination of CIPRO. Emphasis is put on the applications of unmodified and modified carbon-based electrodes considering the modifier, supporting electrolytes, analytical method, concentration range, limit of detection, and real matrices. Carbon-based electrodes are the most used materials attributed to their commercial availability, reduced cost, high chemical stability, and non-toxicity.

High-efficiency (>20%) planar carbon-based perovskite solar cells through device configuration engineering

Carbon-based perovskite solar cells (C-PSCs) have attracted widespread research interest because of their excellent stability. However, the power conversion efficiency (PCE) of C-PSCs, especially planar C-PSCs, lags far behind the certified efficiency (25.5%) of metal-based PSCs. The simple architecture of planar C-PSCs imparts stringent requirements for device configuration. In this study, we fabricated high-performance planar C-PSCs through device configuration engineering in terms of the perovskite active layer and carbon electrode. Through the combination of component and additive engineering, the crystallization and absorption profiles of perovskite active layer have been improved, which afforded sufficient photogenerated carriers and decreased nonradiative recombination. Furthermore, the mechanical and physical properties of carbon electrode were evaluated comprehensively to regulate the back-interface contact. Based on the compromise of the flexibility and conductivity of carbon film, an excellent back-interface contact has been formed, which promoted fast interface charge transfer, thereby decreasing interface recombination and improving carrier collection efficiency. Finally, the as-prepared devices achieved a remarkable PCE of up to 20.04%, which is a record-high value for planar C-PSCs. Furthermore, the as-prepared devices exhibited excellent long-term stability. After storage for 1000 h at room temperature and 25% relative humidity without encapsulation, the as-prepared device retained 94% of its initial performance.

A double perovskite participation for promoting stability and performance of Carbon-Based CsPbI2Br perovskite solar cells

All-inorganic perovskite materials (Typically: CsPbI₂Br) have attracted enormous attention due to their illustrious thermal stability and appropriate bandgap, and their use in perovskite solar cells (PSCs) has been extensively investigated. However, the inevitable defects of the perovskite layer, energy level mismatch between perovskite and carbon electrodes, and the phase instability of CsPbI₂Br limit the power conversion efficiency (PCE) and stability of carbon-based CsPbI₂Br PSCs. Herein, we demonstrate a simple and effective strategy for regulating energy level, inhibiting carrier recombination, and delaying the degradation of perovskite by modifying the surface of CsPbI₂Br with a new type of 2D perovskite Cs₂PtI₆. The carbon-based CsPbI₂Br PSCs achieve a higher PCE (13.69 %) than the control device (11.10 %). The excellent matching of the energy level and suppression of charge carrier recombination should be responsible for the improvement in efficiency. Furthermore, the excellent hydrophobic performance of Cs₂PtI₆ enhances the moisture resistance of the device. This study provides a potential strategy for improving the performance and stability of all-inorganic CsPbI₂Br PSCs.

n-type absorber by Cd2+ doping achieves high-performance carbon-based CsPbIBr2 perovskite solar cells

High efficiency and stability have long been the key issues faced by perovskite solar cells (PSCs). It is found that the CsPbIBr₂ all-inorganic perovskite has a suitable band gap and satisfactory stability, so it has attracted much attention. However, the many defects in the CsPbIBr₂ film are one of the main problems hindering the improvement of power conversion efficiency (PCE) of the CsPbIBr₂ PSCs. The substitution of trace impurities is undoubtedly a simple, cost-effective and efficient strategy. In this work, an appropriate amount of Cd²⁺ (1.0% mol of Pb²⁺) is added into the CsPbIBr₂ precursor solution to fabricate high quality CsPbIBr₂ film with improved crystallinity, reduced trap density, suppressed photo-generated carrier recombination, displayed n-type doping and optimized energy level alignment. The corresponding carbon-based all-inorganic Cd²⁺-doped CsPbIBr₂ PSCs achieve a maximum PCE of 10.63% with a high open circuit voltage (V_OC) of 1.324 V, which are much higher than those of the control one with a PCE of 8.48% and an V_OC of 1.235 V. The unencapsulated device can still retain more than 92% of the initial PCE when stored at ambient atmosphere (25 °C, relative humidity about 30%) for 40 days.

Development of highly sensitive electrochemical sensor using new graphite/acrylonitrile butadiene styrene conductive composite and 3D printing-based alternative fabrication protocol

Here, a novel electrically conductive thermoplastic material composed of graphite/acrylonitrile butadiene styrene (G/ABS) is reported for the first time. This material was explored on the production of 3D printing-based electrochemical sensors with enhanced sensitivity using a novel fabrication approach. The developed G/ABS electrodes showed lower charge transfer resistance (157 vs. 3279 Ω), higher electroactive area (0.61 vs. 0.19 cm²) and peak currents ca. 69% higher when compared with electrodes fabricated using carbon black/polylactic acid (CB/PLA) commercial filament, which has been widely explored in recent literature. Moreover, the G/ABS sensor provided satisfactory repeatability, reproducibility and stability (relative standard deviations (RSDs) were 1.14%, 6.81% and 10.62%, respectively). This improved performance can be attributed to the fabrication protocol developed here, which allows the incorporation of greater amounts of conductive material in the polymeric matrix. The G/ABS electrode also required a simpler and quicker protocol for activation when compared to CB/PLA. As proof of concept, the G/ABS sensor was employed for electroanalytical quantification of paracetamol (PAR) in pharmaceutical products. The linear concentration range was observed from 0.20 to 30 μmol L^-1 and the limit of detection achieved was 54 nmol L^-1, much lower than several recent studies dealing with the same analyte. The sensitivity of the G/ABS electrode regarding PAR was also far better when compared to CB/PLA sensor (0.50 μA/μmol L^-1 vs. 0.12 μA/μmol L^-1). Analyses in commercial pill samples showed good accuracy (recoveries ca. 108%) and precision (RSDs < 5%), suggesting great potential for use of this novel conductive thermoplastic in electroanalytical applications based on 3D printing.

Easy Strategy to Enhance Thermal Stability of Planar PSCs by Perovskite Defect Passivation and Low-Temperature Carbon-Based Electrode

Organic-inorganic lead halide perovskite has recently emerged as an efficient absorber material for solution process photovoltaic (PV) technology, with certified efficiency exceeding 25%. The development of low-temperature (LT) processing is a challenging topic for decreasing the energy payback time of perovskite solar cell (PSC) technology. In this context, the LT planar n-i-p architecture meets all the requirements in terms of efficiency, scalability, and processability. However, the long-term stability of the LT planar PSC under heat and moisture stress conditions has not been carefully assessed. Here, a detailed study on thermal and moisture stability of large-area (1 cm²) LT planar PSCs is presented. In particular, the key role in thermal stability of potassium iodide (KI) insertion in the perovskite composition is demonstrated. It is found that defect passivation of triple-cation perovskite by KI doping inhibits the halide migration induced by thermal stress at 85 °C and delays the formation of degradation subproducts. T80, defined as the time when the cell retains 80% of initial efficiency, is evaluated both for reference undoped devices and KI-doped ones. The results show that T80 increases 3 times when KI doping is used. Moreover, an HTL-free architecture where the Au top electrode is replaced with low-T screen-printable carbon paste is proposed. The combination of the carbon-based HTL-free architecture and KI-doped perovskite permits T80 to increase from 40 to 414 h in unsealed devices.

Penetrating glassy carbon neural electrode arrays for brain-machine interfaces

This paper presents a fabrication method for glassy carbon neural electrode arrays that combines 3D printing and chemical pyrolysis technology. The carbon electrodes have excellent biological compatibility and can be used in neural signal recording. A pretreated Si wafer is used as the substrate for 3D printing, and then, stereolithography 3D printing technology is employed to print photosensitive resin into a cone shape. Next, chemical pyrolysis is applied to convert the 3D prints into glassy carbon electrodes and modify the electrochemical performance of the carbon electrodes. Finally, the glassy carbon electrodes are packed with conductive wires and PDMS. The proposed fabrication method simplifies the manufacturing process of carbon materials, and electrodes can be fabricated without the need of deep reactive ion etching (DRIE). The height of the carbon electrodes is 1.5 mm, and the exposure area of the tips is 0.78 mm², which is convenient for the implantation procedure. The specific capacitance of the glassy carbon arrays is higher than that of a platinum electrode (9.18 mF/cm² vs 3.32 mF/cm², respectively), and the impedance at 1 kHz is lower (7.1 kΩ vs 8.8 kΩ). The carbon electrodes were tested in vivo, and they showed excellent performance in neural signal recording. The signal-to-noise ratio of the carbon electrodes is 50.73 ± 6.11, which is higher than that of the Pt electrode (20.15 ± 5.32) under the same testing conditions. The proposed fabrication method of glassy carbon electrodes provides a novel approach to manufacture penetrating electrodes for nerve interfaces in biomedical engineering and microelectromechanical systems.

Flow micropillar array electroporation to enhance size specific transfection to a large population of cells

Despite serving as a popular non-viral delivery approach, electroporation carries several drawbacks in its current configurations. We developed a Flow Micropillar-array Electroporation (FME) system to wisely regulate an important transmembrane-determining factor, namely cell size variations among individual cells, to achieve effective transfection. In FME, cells flow through a slit-type microfluidic channel on which carbon electrodes with well-patterned micropillar array texture are integrated as the top and bottom wall. Gravity helps bring cells to the micropillar array surface so that the permeable area on cells in different size populations is specified by their size regardless their random location fact. Without sacrificing cell viability, we demonstrate this FME concept by delivering DNA plasmids to several mammalian cell lines with obvious transfection enhancement when compared to a commercial system (K562: 3.0 folds; A549: 3.3 folds; HeLa: 1.8 folds, COS7: 1.7 folds; 293T: 2.9 folds; mES: 2.5 folds). Moreover, carbon-based electrodes are less expensive, more durable, and convenient for integration with a microfluidic setup which enables rapid and massive transfection capability that many therapeutic application needs. The success of FME may benefit many emerging biological studies and clinical practice that requires effective transfection to a large population of cells in limited processing time.

Efficient Carbon-Based CsPbBr3 Inorganic Perovskite Solar Cells by Using Cu-Phthalocyanine as Hole Transport Material

Metal halide perovskite solar cells (PSCs) have attracted extensive research interest for next-generation solution-processed photovoltaic devices because of their high solar-to-electric power conversion efficiency (PCE) and low fabrication cost. Although the world's best PSC successfully achieves a considerable PCE of over 20% within a very limited timeframe after intensive efforts, the stability, high cost, and up-scaling of PSCs still remain issues. Recently, inorganic perovskite material, CsPbBr₃, is emerging as a promising photo-sensitizer with excellent durability and thermal stability, but the efficiency is still embarrassing. In this work, we intend to address these issues by exploiting CsPbBr₃ as light absorber, accompanied by using Cu-phthalocyanine (CuPc) as hole transport material (HTM) and carbon as counter electrode. The optimal device acquires a decent PCE of 6.21%, over 60% higher than those of the HTM-free devices. The systematic characterization and analysis reveal a more effective charge transfer process and a suppressed charge recombination in PSCs after introducing CuPc as hole transfer layer. More importantly, our devices exhibit an outstanding durability and a promising thermal stability, making it rather meaningful in future fabrication and application of PSCs.

A novel fabrication method of carbon electrodes using 3D printing and chemical modification process

Three-dimensional (3D) printing is an emerging technique in the field of biomedical engineering and electronics. This paper presents a novel biofabrication method of implantable carbon electrodes with several advantages including fast prototyping, patient-specific and miniaturization without expensive cleanroom. The method combines stereolithography in additive manufacturing and chemical modification processes to fabricate electrically conductive carbon electrodes. The stereolithography allows the structures to be 3D printed with very fine resolution and desired shapes. The resin is then chemically modified to carbon using pyrolysis to enhance electrochemical performance. The electrochemical characteristics of 3D printing carbon electrodes are assessed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The specific capacitance of 3D printing carbon electrodes is much higher than the same sized platinum (Pt) electrode. In-vivo electromyography (EMG) recording, 3D printing carbon electrodes exhibit much higher signal-to-noise ratio (40.63 ± 7.73) than Pt electrodes (14.26 ± 6.83). The proposed biofabrication method is envisioned to enable 3D printing in many emerging applications in biomedical engineering and electronics.

Retrieval of Au, Ag, Cu precious metals coupled with electric energy production via an unconventional coupled redox fuel cell reactor

The recovery of heavy metals from aqueous solutions or e-wastes is of upmost importance. Retrieval of Au, Ag, and Cu with electricity generation through building an ethanol-metal coupled redox fuel cells (CRFCs) is demonstrated. The cell was uniquely assembled on PdNi/C anode the electro-oxidation of ethanol takes place to give electrons and then go through the external circuit reducing metal ions to metallic on the cathode, metals are recovered. Taking an example of removal of 100mgL^-1 gold in 0.5M HAc-NaAc buffer solution as the catholyte, 2.0M ethanol in 1.0M alkaline solution as the anolyte, an open circuit voltage of 1.4V, more than 96% of gold removal efficiency in 20h, and equivalent energy production of 2.0kWhkg^-1 of gold can be readily achieved in this system. When gold and copper ions coexist, it was confirmed that metallic Cu is formed on the cathodic electrode later than metallic Au formation by XPS analysis. Thus, this system can achieve step by step electrodeposition of gold and copper while the two metal ions coexisting. This work develops a new approach to retrieve valuable metals from aqueous solution or e-wastes.

Comparison of unusual carbon-based working electrodes for electrochemiluminescence sensors

In this work, unconventional carbon-based materials were investigated for use in electrochemiluminescence (ECL) working electrodes. Precursors such as bamboo, pistachio shells, kevlar^® fibers and camphor were differently treated and used as working electrodes in ECL experiments. After a proper process they were assembled as electrodes and tested in an electrochemical cell. Comparison among them and with a commercial glassy carbon electrode (GCE) shows a very good response for all of them thus demonstrating their potential use as disposable low-cost electrodes for early detection electrochemical analysis.

Highly porous activated carbons from resource-recovered Leucaena leucocephala wood as capacitive deionization electrodes

Highly porous activated carbons were resource-recovered from Leucaena leucocephala (Lam.) de Wit. wood through combined chemical and physical activation (i.e., KOH etching followed by CO2 activation). This invasive species, which has severely damaged the ecological economics of Taiwan, was used as the precursor for producing high-quality carbonaceous electrodes for capacitive deionization (CDI). Carbonization and activation conditions strongly influenced the structure of chars and activated carbons. The total surface area and pore volume of activated carbons increased with increasing KOH/char ratio and activation time. Overgasification induced a substantial amount of mesopores in the activated carbons. In addition, the electrochemical properties and CDI electrosorptive performance of the activated carbons were evaluated; cyclic voltammetry and galvanostatic charge/discharge measurements revealed a typical capacitive behavior and electrical double layer formation, confirming ion electrosorption in the porous structure. The activated-carbon electrode, which possessed high surface area and both mesopores and micropores, exhibited improved capacitor characteristics and high electrosorptive performance. Highly porous activated carbons derived from waste L. leucocephala were demonstrated to be suitable CDI electrode materials.

Adsorption and catalytic activity of glucose oxidase accumulated on OTCE upon the application of external potential

This article describes the adsorption of glucose oxidase (GOx) onto optically transparent carbon electrodes (OTCE) under the effect of applied potential and the analysis of the enzymatic activity of the resulting GOx/OTCE substrates. In order to avoid electrochemical interferences with the enzyme redox center, control electrochemical experiments were performed using flavin adenine dinucleotide (FAD) and GOx/OTCE substrates. Then, the enzyme adsorption experiments were carried out as a function of the potential applied (ranged from the open circuit potential to +950mV), the pH solution, the concentration of enzyme, and the ionic strength on the environment. The experimental results demonstrated that an increase in the adsorbed amount of GOx on the OTCE can be achieved when the potential was applied. Although the increase in the adsorbed amount was examined as a function of the potential, a maximum enzymatic activity was observed in the GOx/OTCE substrate achieved at +800mV. These experiments suggest that although an increase in the amount of enzyme adsorbed can be obtained by the application of an external potential to the electrode, the magnitude of such potential can produce detrimental effects in the conformation of the adsorbed protein and should be carefully considered. As such, the article describes a simple and rational approach to increase the amount of enzyme adsorbed on a surface and can be applied to improve the sensitivity of a variety of biosensors.

Integration of a graphite/poly(methyl-methacrylate) composite electrode into a poly(methylmethacrylate) substrate for electrochemical detection in microchips

Traditional fabrication methods for polymer microchips, the bonding of two substrates together to form the microchip, can make the integration of carbon electrodes difficult. We have developed a simple and inexpensive method to integrate graphite/PMMA composite electrodes (GPCEs) into a PMMA substrate. These substrates can be bonded to other PMMA layers using a solvent-assisted thermal bonding method. The optimal composition of the GPCEs for electrochemical detection was determined using cyclic voltammetry with dopamine as a test analyte. Using the optimized GPCEs in an all-PMMA flow cell with flow injection analysis, it was possible to detect 50 nM dopamine under the best conditions. These electrodes were also evaluated for the detection of dopamine and catechol following separation by MCE.

Low-cost flexible nano-sulfide/carbon composite counter electrode for quantum-dot-sensitized solar cell

Cu2S nanocrystal particles were in situ deposited on graphite paper to prepare nano-sulfide/carbon composite counter electrode for CdS/CdSe quantum-dot-sensitized solar cell (QDSC). By optimization of deposition time, photovoltaic conversion efficiency up to 3.08% was obtained. In the meantime, this composite counter electrode was superior to the commonly used Pt, Au and carbon counter electrodes. Electrochemical impedance spectra further confirmed that low charge transfer resistance at counter electrode/electrolyte interface was responsible for this, implied the potential application of this composite counter electrode in high-efficiency QDSC.