Organic dyes containing coplanar dihexyl-substituted dithienosilole groups for efficient dye-sensitised solar cells

peer-reviewedA chromophore containing a coplanar dihexyl-substituted dithienosilole (CL1) synthesised for use in dye-sensitised solar cells displayed an energy conversion efficiency of 6.90% under AM 1.5 sunlight irradiation. The new sensitiser showed a similar fill factor and open-circuit voltage when compared with N719. Impedance measurements showed that, in the dark, the charge-transfer resistance of a cell using CL1 in the intermediate-frequency region was higher compared to N719 (69.8 versus 41.3 Omega). Under illumination at AM 1.5G-simulated conditions, the charge-transfer resistances were comparable, indicative of similar recombination rates by the oxidised form of the redox couple. The dye showed instability in ethanol solution, but excellent stability when attached to TiO2. Classical molecular dynamics indicated that interactions between ethanol and the dye are likely to reduce the stability of CL1 in solution form. Time-dependent density functional theory studies were performed to ascertain the absorption spectrum of the dye and assess the contribution of various transitions to optical excitation, which showed good agreement with experimental results.PUBLISHEDpeer-reviewe

Renewable energy technologies and its adaptation in an urban environment

Optoelectronic Materials and Thin Films: OMTAT 2013. Kochi, Kerala, India, 3–5 January 2013This general article is based on the inaugural talk delivered at the opening of OMTAT 2013 conference. It notes that the integration of renewable energy sources into living and transport sectors presents a daunting task, still. In spite of the fact that the earth and its atmosphere continually receive 1.7 × 1017 watts of radiation from the sun, in the portfolio of sustainable and environment friendly energy options, which is about 16% of the world’s energy consumption and mostly met by biomass, only a paltry 0.04% is accredited to solar. First and second generation solar cells offer mature technologies for applications. The most important difficulty with regards to integration with structures is not only the additional cost, but also the lack of sufficient knowledge in managing the available energy smartly and efficiently. The incorporation of PV as a part of building fabric greatly reduces the overall costs compared with retrofitting. BIPV (Building Integrated photovoltaic) is a critical technology for establishing aesthetically pleasing solar structures. Infusing PV and building elements is greatly simplified with some of the second generation thin film technologies now manufactured as flexible panels. The same holds true for 3rd generation technologies under development such as, and dye- and quantum dot- sensitized solar cells . Additionally, these technologies offer transparent or translucent solar cells for incorporation into windows and skylights. This review deals with the present state of solar cell technologies suitable for BIPV and the status of BIPV applications and its future prospects.SFI-Airtricity Stokes professorship grantEuropean Commissio

Promising grafting strategies on cellulosic backbone through radical polymerization processes – A review

[Display omitted] •Formulation of cellulosic derivative by exploiting radical polymerization method (RPM) is discussed.•Activation of cellulosic texture has been described.•Monomer’s grafting onto cellulosic texture from suitable initiators have been elaborated.•Radiation indulged system promote the performance of RPM.•Controlled radical polymerization triggers the cellulose grafting reaction in block polymerization style. Cellulose is an abundant organic substance found in natural polymer, consists of a linear chain of β glucose residue, which ties from the 1, 4 linkage. Owing to their incredible properties such as bio-renewable, specific tensile strength and bio-degradable, it is being enormously using as a paperboard, drug delivery, fiber production, food packing material, sensitized solar cell, biosorbent, pickering emulsion stabilizer, and battery separator in the modern age of the lithium-ion battery. This review principally points out the radical polymerization method (RPM) for fabricating cellulose derivative. By exploiting RPM, new and improved properties indulging polymer composite of cellulose can successfully fix up by the reaction with the small organic fragment (monomer) such as a methacrylate, methacrylamide, styrene, and butadiene, etc. Radical polymerization has been striking for a long time, due to their procurable process-ability among all the polymerization methods. The most commonly used initiators such as Fenton's reagent, potassium persulfate, and ceric ammonium nitrate are being using to engender free radicals on the cellulose backbone. Other free radical generating techniques like radiation technique (UV + photoinitiator, gamma radiation), plasma treatment, and controlled radical polymerization are being using for grafting purposes. The review summarizes to traditional grafting strategy by common initiators and currently utilizing controlled radical polymerization (CRP) chemistry for polymer synthesis. These methods allow for the formation of functional cellulose, which may possess renovated physical and chemical properties

Succinonitrile-based solid-state electrolytes for dye-sensitised solar cells

Succinonitrile (SCN), a solid ion conductor (10−4 to 10−3 S/cm) in solid form at room temperature, is mixed with either 1,2-dimethyl-3-propylimidazoliuum iodide or 1-butyl-3-methyl imidazolium iodide ionic liquids for forming a solid plastic phase electrolyte for use in dye-sensitised solar cell (DSSC). Cells containing these two electrolytes showed best energy conversion efficiencies of 6.3% and 5.6%, respectively. The commonly used DSSC electrolyte additives inhibit the formation of the SCN plastic phase. However, for the first time, an SCN-additive (additive = guanidinium thiocyanate) electrolyte composition is reported here, which remains as a solid at room temperatures. By using these new solid electrolytes, a simple and rapid single-step filling procedure for making solid-state DSSC is outlined. This process, which reduces the required manufacturing steps from four to one, is most suitable for continuous, high-throughput, commercial DSSC manufacturing lines. These new electrolytes have been tested under low incident light levels (200 lx) to investigate their suitability for indoor DSSC applicationsEuropean Commission - Seventh Framework Programme (FP7)Irish Research Council for Science, Engineering and TechnologyScience Foundation Irelan

Water-Based Synthesis of Novel Hybrid Material of Sulfated Polysaccharide Through Radical Polymerization Process

Water-soluble “sulfated polysaccharides of Chaetomorpha antennina” (CMsps) seaweed were isolated and fractionated (charged & neutral) using column chromatography followed by modification with acrylamide (AAm) to get novel hybrid materials. This polysaccharide comprises 6.356 polydispersity which ascribes to their branching behavior. The crude polysaccharides consist of ribose, arabinose, xylose, and galactose, carbohydrates units. The peak that appeared in the FT-IR spectrum at 1250 cm−1 confirms the sulfated nature of polysaccharides. The charged polysaccharides, pronounced “control CMsps” before the modification, were modified with AAm under microwave irradiation and characterized to investigate potential grafting. FT-IR, SEM, C13NMR, TGA, XRD, CD, and optical rotation were applied for control CMsps and CMsps-g-PAAm (grafted product). The FT-IR and SEM tools have significant capability to prove occurring successful potential grating with fluctuating peaks and morphology, respectively. XRD graphs for materials “control CMsps and CMsps-g-PAAm” reaffirm the successful grafting, leading to symmetrical molecular construction. TGA graphs support the exclusive thermal stability of CMsps-g-PAAm rather than control CMsps. The varying peak/trough ratio was evaluated by the CD spectrum, which identified the reversal change in the chirotopical profile with the insertion of polyacrylamide (PAAm) in polysaccharide chains. The materials, control CMsps and CMsps-g-PAAm were capable to develop hydrogel hence it can be exploited as a promising rheological modifier for food industry applications. The materials can also be useful in the biomedical field as demulcent drug formulation, dental impression product, and drug delivery for local therapy

The optimisation of dye sensitised solar cell working electrodes for graphene and SWCNTs containing quasi-solid state electrolytes

In this study, we report improved power conversion efficiencies of various carbon based quasi-solid state electrolytes/DSSCs by optimising the thickness of TiO2 layer, incorporation of TiO2 scattering layer and application of dense compact surface layers of TiO2 on working electrodes. Single wall carbon nanotube (SWCNT) based quasi-solid state electrolytes showed increased power conversion efficiencies from 1.43% to 3.49%. For the mixture of graphene and SWCNTs the power conversion efficiencies improved from 2.50% to 2.93%. However, graphene based quasi-solid state electrolytes displayed small decreases in power conversion efficiencies from 2.10% to 1.96% due to the more viscous nature of this electrolyte. Electrochemical Impedance Spectroscopy (EIS) demonstrated that the addition of these various carbon based nanomaterials into PMII significantly decreases the charge transfer resistance at the counter electrode and hence the much better performance obtained with carbon based quasi-solid state electrolytes compared to pure PMII based DSSCs.Irish Research Council for Science, Engineering and TechnologyScience Foundation IrelandEuropean UnionMinistry of Education and Science of the Russian Federatio