Coumarin-based D–π–A dyes for efficient DSSCs: DFT and TD-DFT study of the π-spacers influence on photovoltaic properties

Research on Chemical Intermediates - A series of D–π–A architectures dyes with Coumarin-based derivatives as difluorenylaminocoumarin (DF) and diphenylaminocoumarin (DP) have been...     

New materials based on thiazolothiazole and thiophene candidates for optoelectronic device applications: theoretical investigations

We report theoretical analysis on the geometries and electronic properties of new conjugated compounds based on thiazolothiazole synthesized by Ando et al. (Synth. Met., 156:327 [13]). The theoretical ground-state geometry and electronic structure of the studied molecules were investigated by the density functional theory (DFT) method at Becke’s three-parameter functional and Lee–Yang–Parr functional (B3LYP) level with 6-31G(d,p) basis set. The effects of the ring structure and the substituents on the geometries and electronic properties of these materials are discussed to investigate the relationship between molecular structure and optoelectronic properties. This investigation was used to drive further syntheses towards compounds more useful as active optoelectronic materials. Theoretical knowledge of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of the components is basic in studying organic solar cells, so the HOMO, LUMO, and gap energy V _oc (open-circuit voltage) of the studied compounds are calculated and discussed. These properties suggest these materials as good candidates for use in organic dye-sensitized solar cells.     

Enhanced CO2 adsorptivity of SWCNT by polycyclic aromatic hydrocarbon intercalation

We tuned the electronic properties of single wall carbon nanotube (SWCNT) with intercalation of naphthalene derivatives (NDs) having different electron donor or acceptor property in the SWCNT bundles. Characterization of the adsorbed SWCNT with Raman spectroscopy and electrical conductivity measurement clearly indicate the charge transfer interaction of ND molecules with SWCNT. Also X-ray diffraction supports the intercalation of ND molecules in the interstitial spaces and groove sites of SWCNT bundle. Intercalation of ND molecules enhances remarkably the CO₂ adsorptivity, which can be ascribed to the key importance of the interaction of the quadrupole moment of CO₂ with the local electrical field on the SWCNT induced by the charge transfer interaction.     

DFT and TD-DFT calculations on thieno[2,3-b]indole-based compounds for application in organic bulk heterojunction (BHJ) solar cells

Research on Chemical Intermediates - Eight novel organic compounds with donor–π–acceptor (D–π–A) structure were designed for use as donors in organic bulk...     

Benzocarbazole-based D–Di–π–A dyes for DSSCs: DFT/TD-DFT study of influence of auxiliary donors on the performance of free dye and dye–TiO2 interface

Research on Chemical Intermediates - A series of ten organic dyes Ai (i=1–10) of type D–Di–π–A (i=2–10) combining various auxiliary donors (Di) with the same...     

Gold and silver nanoparticles and indicator dyes as active agents in colorimetric spot and strip tests for mercury(II) ions: a review

This review with 111 references covers recent progress made in the field of strip tests and spot tests for quantitative determination of mercury(II) ions. Following an introduction into the subject and the fundamentals of colorimetric determination, we first cover methods for synthesis and characterization of gold and silver nanoparticles (NPs) and give representative examples. The next sections cover (a) methods for dye-based detection of Hg(II) ions (categorized into azo, acridine, anthraquinone, di?/triarylmethane, nitro/nitroso, cyanine, triazole, oxazine, thiazine, dioxazine and xanthene dyes), and (b) techniques for immobilization of active agents (NPs and indicators) on the solid support. A conclusion section discusses current challenges and trends in future research.

Open image in new window

Graphical abstract This review summarizes recent progress made in the field of strip tests and spot tests for quantitative determination of mercury(II) ions by using gold and silver nanoparticles (NPs).

     

Nanocellulose characteristics from the inner and outer layer of banana pseudo-stem prepared by TEMPO-mediated oxidation

Many tonnes of agricultural wastes are generated annually, which contains a relatively high amount of cellulose; banana pseudo-stem is one waste type that is a promising material for nanocellulose production. This research characterised nanocellulose from inner and outer layers of banana pseudo-stem as a preliminary research strategy for designing biodegradable packaging material from banana pseudo-stem nanocellulose. Nanocellulose was successfully prepared through TEMPO (2,2,6,6-tetramethylpiperidine 1-oxyl)-mediated oxidation. The extracted nanocellulose from both the inner and outer layers had observed widths of approximately 7–35 nm and long fibrillated fibre. They had high negative zeta potential (lower than ?33.6) that provided good colloidal stability. The purity of the nanocellulose was high as demonstrated by ¹³C solid-state NMR and Fourier transform infrared spectroscopy. Nanocellulose from both layers was significantly more crystalline than the raw materials. Thermal stability of nanocellulose sourced from inner and outer layers was relatively similar, with degradation temperature of approximately 220 °C, which was slightly lower than the degradation temperature of its native form (232 °C for inner layer and 261 °C for outer layer).     

Offretite Zeolite Single Crystals Synthesized by Amphiphile-Templating Approach

Offretite zeolite synthesis in the presence of cetyltrimethylammonium bromide (CTABr) is reported. The offretite crystals were synthesized with a high crystallinity and hexagonal prismatic shape after only 72 h of hydrothermal treatment at 180 °C. The CTABr has dual-functions during the crystallization of offretite, viz. as structure-directing agent and as mesoporogen. The resulting offretite crystals, with a Si/Al ratio of 4.1, possess more acid sites than the conventional offretite due to their high crystallinity and hierarchical structure. The synthesized offretite is also more reactive than its conventional counterpart in the acylation of 2-methylfuran for biofuel production under non-microwave instant heating condition, giving 83.5% conversion with 100% selectivity to the desired product 2-acetyl-5-methylfuran. Hence, this amphiphile synthesis approach offers another cost-effective and alternative route for crystallizing zeolite materials that require expensive organic templates.     

Novel cytotoxic, polyprenylated heptacyclic xanthonoids from Indonesian Garcinia gaudichaudii (Guttiferae)

[reaction: see text] The structures of novel gaudichaudiic acids F-I (1-4), isolated from the bark of Indonesian Garcinia gaudichaudii, have been elucidated by detailed spectral analysis. Gaudichaudiic acid I (4) is probably derived from 1 as a result of allylic oxidation at C-24 and C-21, followed by aromatization.