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Here we investigated the photo response behaviour of p -Cu _2 CdSnS _4 ( p -CCTS)/ n -Bi _2 S _3 heterojunction photodiode. The solution processed CCTS films without any high temperature sulfurization demonstrated the photo response behaviour, suggesting the material is well suited for low temperature processed photovoltaic applications. A CCTS film was deposited on an ITO coated glass substrate using simple sol-gel based spin coating method. Current–voltage (I–V) characteristic of the p -CCTS/ n -Bi _2 S _3 heterojunction photodiode showed a good rectifying behaviour indicating better junction formation between CCTS and Bi _2 S _3 layers. The obtained photocurrent is 4 times higher than that of the dark current. The I–V curves are asymmetric with respect to voltages and the photocurrent in the positive bias region is considerably higher than the corresponding values in the negative bias region. With these results, it is concluded that the CdS material in traditional thin film PV devices can be replaced with Bi _2 S _3 for better transportation of charge carriers in the PN -junction.

A polyaniline (PANi)-carbon quantum dots (CQDs) nanocomposite material with CQDs made from a PEG (polyethylene glycol and NaOH) source was synthesized. This unique synthesis technique was developed to overcome the setbacks of the PEG method by using UG (urea and glycine). PANi was synthesized by chemical oxidation in the presence of CQDs, which were prepared according to the two above-mentioned methods. The sample was further characterized by morphological, optical, and electrochemical experiments. FE-SEM showed ridge-like morphology and UV-Vis studies revealed the presence of PANi and CQDs. HRTEM images gave details on the uniformly distributed polyaniline, which showed lengthy rod-like rough surfaces with interconnected tiny CQDs. The electrochemical results from CV and GCD studies indicated an enhancement of the specific capacitance for sample PCQ-2 (CQDs synthesized via the UG method as a source) compared to only PANi and PCQ-1 (CQDs prepared by the PEG method). The cyclic stability established was 84.5% retention from initial capacitance values over 3000 cycles. A two-electrode prototype device was also developed with the PCQ-2 sample and it achieved a reasonable capacitance of 161.3 mF/cm2 and demonstrated good retention stability over 5000 cycles. These results may be due to a variety of factors related to compositing CQDs (with urea and glycine as a source) with PANi.

Nickel cobalt sulfide (NCS) was synthesized from nickel and cobalt nitrate (NCS-1) by a hydrothermal method. In another method, nickel cobalt sulfide (NCS-2) was also synthesized from hydrothermally synthesized nickel cobalt oxide (NCO). The syntheses of NCS-1 and NCO were conducted in the presence of glycine as a templating agent. The NCS and NCO samples were thoroughly characterized by different techniques. XRD studies showed that both NCO and NCS consisted of the cubic crystal phases. Cyclic voltammetry of NCO and NCS revealed that, with an increasing scan rate within the range of 10–100 mV s−1, the specific capacitance of the samples reduced. The specific capacitance of NCS-2, measured by galvanostatic charge–discharge, was found to be 675 F g−1, which is higher than those of NCO (313 F g−1) and NCS-1 (500 F g−1). The specific capacitance retention of NCS-2 was 88% over 1000 cycles, indicating the good cyclic stability of the material. Keywords: Nickel cobaltite, Nickel cobalt sulfide, Glycine, Pseudocapacitor, Supercapacitor

Silver telluride nanowires incorporating silver were prepared by green chemical method in aqueous solution. First, Ag 2TeO 3was prepared from aqueous solutions of sodium tellurite (Na 2TeO 3) and silver nitrate (AgNO 3). At room temperature in basic solution, α- d-glucose reduces Ag 2TeO 3to generate silver nanocrystals, whereas solvothermal reaction of Ag 2TeO 3with α- d-glucose at 165 °C generates Te, Ag, or Ag 2Te−Ag axial hetrojunction nanowires depending upon the pH of the reaction mixture. These heterojunction nanowires, which exhibit electrical bistability at low voltage, can be used as data storage devices. [ABSTRACT FROM AUTHOR]

We form pn-junctions by electrostatic binding of a p-type and an n-type ZnO nanoparticle. Current−voltage characteristics of pn-junctions are rectifying in nature. Individual components of the junction do not show any rectification. An np-junction, formed by reversing the binding sequence of the two types of nanoparticles, shows rectification in the reverse bias direction. By controlling the type of dopants in the ZnO nanoparticles, pn(and np) and nn(and nn) junctions are formed that exhibit rectification. Current rectification in a junction between two nanoparticles shows that a depletion layer may have formed even in the quantum dot regime. [ABSTRACT FROM AUTHOR]

In situ Ag nanoparticles are produced on reduction of Agwith N,N-dimethylformamide in the presence of poly(vinylidene fluoride) (PVF2). The plasmon band transition is monitored with time in the reaction mixture for three sets of experiments by UV−vis spectroscopy. The plasmon band absorbance increases sigmoidally with log(time). Analysis of the data with the Avrami equation yields an exponent nvalue between 1.5 and 2.0, indicating two-dimensional nucleation with linear or diffusion controlled growth. The TEM study of the polymer nanocomposites (PNC) indicates both spherical and rodlike morphology for PNC0.5 and PNC2.5 samples, whereas the PNC11 sample has spherical and agglomerated structures (the numerical number associated with PNC indicates percentage (w/w) of Ag in the nanocomposite). The WAXS and FTIR studies indicate the formation of piezoelectric -polymorphic PVF2in the nanocomposites. The DSC study indicates some increase of the melting point and enthalpy of fusion of PVF2in the nanocomposite, although with increase in Ag nanoparticle concentration the increase is smaller. The crystallization temperatures of PNCs also increased, indicating nucleating effect of Ag nanoparticles in the composite. In the TGA curves, the PNCs exhibit a three-step degradation process. The degradation temperatures of PNCs are lower than that of PVF2. The storage modulus data indicate a significant reinforcement of the mechanical property in the PNCs where also the reinforcement effect decreases with increasing nanoparticle concentration. Both the loss modulus and tan plots indicate two peaks; the lower temperature peak has been attributed for glass transition temperature, whereas the higher one has been attributed to a similar type relaxation process for the crystalline−amorphous interface. The increase in the glass transition is marginal for the PNCs, but the increase of later transition temperature is somewhat higher. The FTIR study shows that the dipolar interaction of the >CF2dipole with the surface charges of Ag nanoparticle stabilizes the nanoparticle in the nanocomposite. [ABSTRACT FROM AUTHOR]

Instant hydrogelation of coumarin-derivatized glycine has been demonstrated in the absence of long-chain hydrophobic groups upon formation of a zinc(ii) coordination polymer, which exhibits fluorescence enhancement upon gelation. [ABSTRACT FROM AUTHOR]

Photosynthesis is the natural eternal process of conversion of solar energy into Chemical energy by living chlorophyllous organisms. The direct conversion of sunlight into electrical current by using photosynthetic organisms has the potential to produce green energy. Conventional bio-photovoltaic cells have utilized unicellular photosynthetic microorganisms such as cyanobacteria and unicellular green algae. This study describes electricity generation through a quasi-solid-state device by utilizing live freshwater macroalgae. Here, we fabricated a simple bio-photovoltaic device with filamentous macroalgae Pithophora roettleri as photoactive materials. The filamentous alga Pithophora belonging to the family of green algae, is generally found growing at the bottom or forming dense mats on the surface of aquatic habitats. The algae were collected from a pond located in the neighbourhood and fabricated a device by sandwiching the algal biofilm between activated carbon-coated copper (Cu) and titanium oxide (TiO2) coated fluorine-doped tin oxide (FTO) coated glass slide. The fabricated optimized device has exhibited a considerable amount of photo-generated current and photo-generated voltage generation under the white light and UV light irradiation The optimized device (with 1 cm2 area) exhibits 10.19 μA short circuit photocurrent and 0.35 V open circuit photovoltage in white light (100 mW/cm2) irradiance and exhibits 1.25 mA photocurrent and 0.5 V photovoltage in UV light (365 nm LED with 20 mW/cm2 intensity). To understand applicability, 10 devices were connected in a series that delivered 5.53 V in outdoors under natural sunlight with 0.6 Sun intensity.

In this work, a wire-shaped perovskite solar cell based on TiO2 nanotube (TNT) arrays is demonstrated for the first time by integrating a perovskite absorber on TNT-coated Ti wire. Anodization was adopted for the conformal growth of TNTs on Ti wire, together with the simultaneous formation of a compact TiO2 layer. A sequential step dipping process is employed to produce a uniform and compact perovskite layer on top of TNTs with conformal coverage as the efficient light absorber. Transparent carbon nanotube film is wrapped around Ti wire as the hole collector and counter electrode. The integrated perovskite solar cell wire by facile fabrication approaches shows a promising future in portable and wearable textile electronics. [ABSTRACT FROM AUTHOR]

The rising energy ultimatum has urged a paradigm shift from conventional to non-conventional, green, and clean energy sources to indulge supply and demand. In light of this, manganese-doped polyaniline was synthesized via the In-situ oxidative polymerization method and was employed as material for supercapacitor electrodes. The doping of PANI by manganese was confirmed from EDX and XPS analysis. Electrochemical studies uncovered an areal capacitance of 776 mF/cm2 at a current density of 1 mA/cm2, gravimetric capacitance of 995 F/g at 1 A/g, 99% coulombic efficiency, and a capacitive retention of 86.5% was observed after 20,000 cycles at a current density of 35 mA/cm2 by the fabricated coin cell device. The shelf life performance of the coin cell was analyzed after 400 days and underwent a long run for one lakh cycles, which revealed a capacitive retention of 71% at 1 mA/cm2 and a stable coulombic efficiency of 96% throughout the cycling. From the performance analysis, the manganese-doped PANI claims to serve as an excellent electrode for supercapacitor applications.