Microwave-assisted ultrafast in-situ growth of N-doped carbon quantum dots on multiwalled carbon nanotubes as an efficient electrocatalyst for photovoltaics.

Multiwalled carbon nanotubes (MWCNTs) are at the forefront of metal-free electrocatalysts, however, the performance is still limited due to lack of functionality and dispersion. Coupling of MWCNTs with nitrogen doped carbon quantum dots (NCQDs) can impart the required active sites and dispersion. For the purpose, NCQDs are generally attached to MWCNTs by multistep processing, such as NCQDs synthesis, followed by their complex purification, surface activation, and crosslinking with MWCNT. The scalability of such a multistep process is limited, which is addressed by direct microwave-assisted growth of NCQDs on MWCNT. The concentration of reactants of NCQDs synthesis was optimized (with respect to MWCNTs), to achieve controlled direct growth of NCQDs on MWCNTs. The proposed strategy significantly reduced time and energy consumption, along with providing an overlapped interface for the fast charge transfer. Moreover, NCQDs' growth effectively modulated the surface reactivity and internal band structure of the MWCNTs. In response, dye-sensitized solar cells employing NCQDs modified MWCNT as a counter electrode showed 50% higher photovoltaic performance as compared to bare MWCNTs.

An all carbon dye sensitized solar cell: A sustainable and low-cost design for metal free wearable solar cell devices.

Lightweight carbon electrodes are the new candidates for photovoltaic devices due to their temperature resistivity, ease of fabrication, and skin comfortability. Herein, a sustainable and facile strategy has been proposed for metal free all carbon dye sensitized solar cell (C-DSSC), assembled by stacking carbon front electrode (CFE) and carbon counter electrode (CCE). The CFE demonstrated adequate light transmittance (70-50%) while maintaining efficient photon absorption and charge separation mechanism due to dye coated TiO2 nanorods (P25-R). The graphene dip coated carbon counter electrode (Gr@CCE) possesses remarkable electro catalytic activity towards I3-/I- redox couple with low charge transfer resistance (RCT = 0.79 Ω). The sustainable design of C-DSSC attained ~6 ± 0.5% efficiency with high photocurrent density of 18.835 mA. cm-2. The superior performance of C-DSSC is accredited to its improved charge mobility, low internal resistance, and better interfacial electrode contact. The thickness of C-DSSC is ≤3 mm eliminates the need for rigid glass in DSSC.

Self-assembled nanomanipulation of silica nanoparticles enable mechanochemically robust super hydrophobic and oleophilic textile.

HYPOTHESIS: Non-wettable fabric surfaces with excellent mechanochemical robustness for practical applications have attracted much attention from researchers in recent years. However, such surfaces suffer from stability issues when exposed to harsh environments because of the weak bonding of the functional materials. EXPERIMENTS: A unique facile approach is proposed to enhance the adhesion strength and hydrophobicity by improving the hierarchal roughness and opposite charge attraction using alkali and cationized bovine serum albumin (cBSA) respectively. Alkaline etching generated the microroughness and functional groups which facilitated the enhanced adsorption of material on fiber surfaces. The etched fabrics were further treated with cBSA to introduce the positive charged functional groups which enabled the crosslinking of silica nanoparticles with the fiber surfaces through strong electrostatic attraction. FINDINGS: Benefitting from this novel approach, the improved properties of the samples were confirmed through the water contact angle (WCA), self-cleaning effect, chemical/mechanical stability, and selective absorption of organic solvents. Superhydrophobic fabric with WCA of 171° was fabricated by alkaline etching followed by cationization. Along with the excellent hydrophobicity, superhydrophobic fabric exhibited strong chemical, and mechanical stability and self-cleaning property. The superhydrophobic fabric was utilized for the selective absorption of organic solvents from water because of its superoleophilic characteristics. The significant fabrication strategy and promising performance of superhydrophobic fabrics make these fabrics feasible for large-scale production for various industrial applications i.e. in harsh chemical industries and waste water treatment.

Fabrication of conductive and printable nano carbon ink for wearable electronic and heating fabrics.

Printable Nano carbon colloidal ink has fascinated great attention due to their exceptional potential for large-scale application for powering wearable electronic devices. Though, it is challenging to incorporate various characteristics together such as mechanical stability, solution printability, conductivity, electrocatalytic activity, and heat generating properties in the flexible fabric based electrode system. In this research the development of printable composites made with woven/nonwoven fabrics printed with multiwall carbon nanotubes for flexible and wearable heating system and cathodes for dye-sensitized solar cells (DSSC), respectively. We report a printable carbon ink of multiwall carbon nanotubes (MWCNT) synthesized by globular protein serum bovine albumin (BSA). BSA is amino-rich dispersant used to disperse MWCNT and generate tubular porous carbon matrix. High loading ratio of BSA increases the dispersing power of MWCNT and increased porosity of CNT matrix. The proposed Organic Nanocarbon ink (Organic NC) serve the pathways for electron transport leading to higher heat dissipation as the well high conductivity and electrocatalytic activity. It was interesting to reveal that different kinds of woven and nonwoven fabrics displayed exceptional thermal properties when DC voltage was applied. The heat generating properties were highly dependent on the type of fabric and conductive ink uptake. Our proposed Organic NC printed fabric system exhibited superior conductivity with 15-20â€¯Ω resistivity and lower charge transfer resistance RCT = 2.69 Ω, demonstrated an 8% power conversion efficiency of DSSC. The proposed research paves the ways for solution printable high performance woven and nonwoven conductive and thermoelectric materials for wearable electronics.

Fabrication of a flexible and conductive lyocell fabric decorated with graphene nanosheets as a stable electrode material.

Textile electrodes are highly desirable for wearable electronics as they offer light-weight, flexibility, cost effectiveness and ease of fabrication. Here, we propose the use of lyocell fabric as a flexible textile electrode because of its inherently super hydrophilic characteristics and increased moisture uptake. A highly concentrated colloidal solution of graphene oxide nanosheets (GONs) was coated on to lyocell fabric and was then reduced in to graphene nanosheets (GNs) using facile chemical reduction method. The proposed textile electrode has a very high surface conductivity with a very low value of surface resistance of only 40Ωsq(-1), importantly without use of any binding or adhesive material in the processing step. Atomic force spectroscopy (AFM) and Transmission electron microscopy (TEM) were conducted to study the topographical properties and sheet exfoliation of prepared GONs. The surface morphology, structural characterization and thermal stability of the fabricated textile electrode were studied by field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FT-IR), X ray photon spectroscopy (XPS), Raman spectroscopy, Wide angle X ray diffraction spectroscopy (WAXD) and Thermogravimetric analysis (TGA) respectively. These results suggest that the GONs is effectively adhered on to the lyocell fabric and the conversion of GONs in to GNs by chemical reduction has no adverse effect on the crystalline structure of textile substrate. The prepared graphene coated conductive lyocell fabric was found stable in water and electrolyte solution and it maintained nearly same surface electrical conductivity at various bending angles. The electrical resistance results suggest that this lyocell based textile electrode (L-GNs) is a promising candidate for flexible and wearable electronics and energy harvesting devices.

Highly Functional TNTs with Superb Photocatalytic, Optical, and Electronic Performance Achieving Record PV Efficiency of 10.1% for 1D-Based DSSCs.

Different nanostructures of TiO2 play an important role in the photocatalytic and photoelectronic applications. TiO2 nanotubes (TNTs) have received increasing attention for these applications due to their unique physicochemical properties. Focusing on highly functional TNTs (HF-TNTs) for photocatalytic and photoelectronic applications, this study describes the facile hydrothermal synthesis of HF-TNTs by using commercial and cheaper materials for cost-effective manufacturing. To prove the functionality and applicability, these TNTs are used as scattering structure in dye-sensitized solar cells (DSSCs). Photocatalytic, optical, Brunauer-Emmett-Teller (BET), electrochemical impedance spectrum, incident-photon-to-current efficiency, and intensity-modulated photocurrent spectroscopy/intensity-modulated photovoltage spectroscopy characterizations are proving the functionality of HF-TNTs for DSSCs. HF-TNTs show 50% higher photocatalytic degradation rate and also 68% higher dye loading ability than conventional TNTs (C-TNTs). The DSSCs having HF-TNT and its composite-based multifunctional overlayer show effective light absorption, outstanding light scattering, lower interfacial resistance, longer electron lifetime, rapid electron transfer, and improved diffusion length, and consequently, J SC , quantum efficiency, and record photoconversion efficiency of 10.1% using commercial N-719 dye is achieved, for 1D-based DSSCs. These new and highly functional TNTs will be a concrete fundamental background toward the development of more functional applications in fuel cells, dye-sensitized solar cells, Li-ion batteries, photocatalysis process, ion-exchange/adsorption process, and photoelectrochemical devices.

A Novel Activated-Charcoal-Doped Multiwalled Carbon Nanotube Hybrid for Quasi-Solid-State Dye-Sensitized Solar Cell Outperforming Pt Electrode.

Highly conductive mesoporous carbon structures based on multiwalled carbon nanotubes (MWCNTs) and activated charcoal (AC) were synthesized by an enzymatic dispersion method. The synthesized carbon configuration consists of synchronized structures of highly conductive MWCNT and porous activated charcoal morphology. The proposed carbon structure was used as counter electrode (CE) for quasi-solid-state dye-sensitized solar cells (DSSCs). The AC-doped MWCNT hybrid showed much enhanced electrocatalytic activity (ECA) toward polymer gel electrolyte and revealed a charge transfer resistance (RCT) of 0.60 Ω, demonstrating a fast electron transport mechanism. The exceptional electrocatalytic activity and high conductivity of the AC-doped MWCNT hybrid CE are associated with its synchronized features of high surface area and electronic conductivity, which produces higher interfacial reaction with the quasi-solid electrolyte. Morphological studies confirm the forms of amorphous and conductive 3D carbon structure with high density of CNT colloid. The excessive oxygen surface groups and defect-rich structure can entrap an excessive volume of quasi-solid electrolyte and locate multiple sites for iodide/triiodide catalytic reaction. The resultant D719 DSSC composed of this novel hybrid CE fabricated with polymer gel electrolyte demonstrated an efficiency of 10.05% with a high fill factor (83%), outperforming the Pt electrode. Such facile synthesis of CE together with low cost and sustainability supports the proposed DSSCs' structure to stand out as an efficient next-generation photovoltaic device.

Integrating high electrical conductivity and photocatalytic activity in cotton fabric by cationizing for enriched coating of negatively charged graphene oxide.

Electroconductive textiles have attended tremendous focus recently and researchers are making efforts to increase conductivity of e-textiles, in order to increase the use of such flexible and low cost textile materials. In this study, surface conductivity and photo catalytic activity of standard cotton fabric (SCF) was enhanced by modifying its surface charge, from negative to positive, using Bovine Serum Albumin (BSA) as a cationic agent, to convert it into cationised cotton fabric (CCF). Then, both types of fabrics were dip coated with a simple dip and dry technique for the adsorption of negatively charged graphene oxide (GO) sheets onto its surface. This resulted in 67.74% higher loading amount of GO on the CCF making self-assembly. Finally, this coating was chemically converted by vapor reduction using hydrazine hydrate to reduced graphene oxide (rGO) for restoration of a high electrical conductivity at the fabric surface. Our results revealed that with such high loading of GO, the surface resistance of CCF was only 40Ω/sq as compared to 510Ω/sq of the SCF and a 66% higher photo catalytic activity was also achieved through cationization for improved GO coating. Graphene coated SCF and CCF were characterized using FE-SEM, FTIR, Raman, UV-vis, WAXD, EDX and XPS spectroscopy to ascertain successful reduction of GO to rGO. The effect of BSA treatment on adsorption of cotton fabric was studied using drop shape analyzer to measure contact angle and for thermal and mechanical resistance, the fabric was tested for TGA and tensile strength, respectively. rGO coated fabric also showed slightly improved thermal stability yet a minor loss of strength was observed. The high flexibility, photocatalytic activity and excellent conductivity of this fabric suggests that it can be used as an electrode material for various applications.

Multiwalled carbon nanotube coated polyester fabric as textile based flexible counter electrode for dye sensitized solar cell.

Textile wearable electronics offers the combined advantages of both electronics and textile characteristics. The essential properties of these flexible electronics such as lightweight, stretchable, and wearable power sources are in strong demand. Here, we have developed a facile route to fabricate multi walled carbon nanotube (MWCNT) coated polyester fabric as a flexible counter electrode (CE) for dye sensitized solar cells (DSSCs). A variety of MWCNT and enzymes with different structures were used to generate individual enzyme-dispersed MWCNT (E-MWCNT) suspensions by non-covalent functionalization. A highly concentrated colloidal suspension of E-MWCNT was deposited on polyester fabric via a simple tape casting method using an air drying technique. In view of the E-MWCNT coating, the surface structure is represented by topologically randomly assembled tubular graphene units. This surface morphology has a high density of colloidal edge states and oxygen-containing surface groups which execute multiple catalytic sites for iodide reduction. A highly conductive E-MWCNT coated fabric electrode with a surface resistance of 15 Ω sq(-1) demonstrated 5.69% power conversion efficiency (PCE) when used as a flexible CE for DSSCs. High photo voltaic performance of our suggested system of E-MWCNT fabric-based DSSCs is associated with high sheet conductivity, low charge transfer resistance (RCT), and excellent electro catalytic activity (ECA). Such a conductive fabric demonstrated stable conductivity against bending cycles and strong mechanical adhesion of E-MWCNT on polyester fabric. Moreover, the polyester fabric is hydrophobic and, therefore, has good sealing capacity and retains the polymer gel electrolyte without seepage. This facile E-MWCNT fabric CE configuration provides a concrete fundamental background towards the development of textile-integrated solar cells.

Optimized performance of quasi-solid-state DSSC with PEO-bismaleimide polymer blend electrolytes filled with a novel procedure.

Dye-sensitized solar cell (DSSC) is an attractive renewable energy technology currently under intense investigation. Electrolyte plays an important role in the photovoltaic performance of the DSSCs and many efforts have been contributed to study different kinds of electrolytes with various characteristics such as liquid electrolytes, polymer electrolytes and so on. In this study, DSSC is developed by using quasi-solid electrolyte and a novel procedure is adopted for filling this electrolyte. The quasi-solid-state electrolyte was prepared by mixing Poly ethylene oxide (PEO) and bismaleimide together and constitution was taken as PEO (15 wt%) at various bismaleimide concentrations (1, 3, 5 wt%). The novel procedure of filling electrolyte consists of three major steps (first step: filling liquid electrolyte, second step: vaporization of liquid electrolyte, third step: refilling quasi-solid-state electrolyte). The electrochemical and photovoltaic performances of DSSCs with these electrolytes were also investigated. The electrochemical impedance spectroscopy (EIS) indicated that TiO2/Dye/electrolyte impedance is reduced and electron lifetime is increased, and consequently efficiency of cell has been improved after using this novel procedure. The photovoltaic power conversion efficiency of 6.39% has been achieved under AM 1.5 simulated sunlight (100 W/cm2) through this novel procedure and by using specified blend of polymers.

Enhanced power conversion efficiency of dye-sensitized solar cells using nanoparticle/nanotube double layered film.

To enhance the power conversion efficiency of dye-sensitized solar cell, a new type of double layered photoanode was prepared using TiO2 nanoparticle in under layer and TiO2 nanotube in upper layer. TiO2 nanotubes were synthesized by hydrothermal polymerization. The morphology and the properties were investigated and characterized by Field Emission-Scanning Electron Microscopy (FE-SEM), Field Emission-Transmission Electron Microscopy (FE-TEM), Wide Angle X-ray Diffraction (WAXD), Thermogravimetric analysis (TGA) and, Brunauer-Emmett-Teller test (BET). The light-to-electricity conversion efficiency was improved with the double-layered TiO2 film, which in turn, significantly increases the power conversion efficiency of dye-sensitized solar cells (DSSCs). This is due to large dye adsorption of light-scatters as well as TiO2 main layer. Moreover, rapid electron transport and light-havesting efficiency contributed to high conversion efficiency. The power conversion efficiency of an optimized cell (photoanode consisting of 13-15 microm main-layer and TNT over-layer) was 8.06% under simulated Air mass 1.5 (AM 1.5) global sunlight (1 Sun, 100 mW/cm2).