No abstract

Detection of explosives is of utmost importance due to the threat to human security as a result of illegal transport and terrorist activities. Trinitrotoluene (TNT) is a widely used explosive in landmines and military operations that contaminates the environment and groundwater, posing a threat to human health. Achieving the detection of explosives at a sub-femtogram level using a molecular sensor is a challenge. Herein we demonstrate that a fluorescent organogelator exhibits superior detection capability for TNT in the gel form when compared to that in the solution state. The gel when coated on disposable paper strips detects TNT at a record attogram (ag, 10(-18) g) level (∼12 ag/cm(2)) with a detection limit of 0.23 ppq. This is a simple and low-cost method for the detection of TNT on surfaces or in aqueous solutions in a contact mode, taking advantage of the unique molecular packing of an organogelator and the associated photophysical properties.

Nature excels at engineering materials by using the principles of chemical synthesis and molecular self-assembly with the help of noncovalent forces. Learning from these phenomena, scientists have been able to create a variety of self-assembled artificial materials of different size, shapes, and properties for wide ranging applications. An area of great interest in this regard is solvent-assisted gel formation with functional organic molecules, thus leading to one-dimensional fibers. Such fibers have improved electronic properties and are potential soft materials for organic electronic devices, particularly in bulk heterojunction solar cells. Described herein is how molecular self-assembly, which was originally proposed as a simple laboratory curiosity, has helped the evolution of a variety of soft functional materials useful for advanced electronic devices such as organic field-effect transistors and organic solar cells. Highlights on some of the recent developments are discussed.

Self-organisation is an elegant tool for the creation of assemblies controlled in all dimensions with tunable properties in natural as well as artificial supramolecular systems. Especially, the supramolecular organisation of fullerene (C(60)) using π-stacking interaction to form various functional assemblies is of particular importance as it can provide excellent optoelectronic properties. Interestingly, the insufficient solubility of C(60) has been overcome through the noncovalent interaction with other hosts and covalent functionalisation with organic moieties. This has resulted in supramolecular assemblies at the nano/micro/macro scales under different preparation conditions. The developments in the area of fullerene self-assembly during the last few decades have significantly contributed to the sensible design and fabrication of organic electronic devices. A summary of the very recent reports regarding the organisation of pristine C(60), its coassembly with other hosts, unique polymorphs of fullerene derivatives, functional liquid crystalline assemblies, donor/acceptor heterojunctions and its applications will be presented in this tutorial review. Future research directions in which the supramolecular fullerene assembly may achieve more precision and improve the efficiency of the photovoltaic devices are also discussed.

Nonvolatile room-temperature luminescent molecular liquids are a new generation of organic soft materials. They possess high stability, versatile optical properties, solvent-free fluid behaviour and can effectively accommodate dopant dye molecules. Here we introduce an approach to optimize anthracene-based liquid materials, focussing on enhanced stability, fluorescence quantum yield, colour tunability and processability, with a view to flexible electronic applications. Enveloping the anthracene core in low-viscosity branched aliphatic chains results in stable, nonvolatile, emissive liquid materials. Up to 96% efficient energy-transfer-assisted tunable emission is achieved by doping a minute amount of acceptor dye in the solvent-free state. Furthermore, we use a thermoresponsive dopant to impart thermally controllable luminescence colours. The introduced strategy leading to diverse luminescence colours at a single blue-light excitation can be an innovative replacement for currently used luminescent materials, providing useful continuous emissive layers in developing foldable devices.

Proton-exchange membrane fuel cells are promising energy devices for a sustainable future due to green features, high power density, and mild operating conditions. A facile proton-conducting membrane plays a pivotal role to boost the efficiency of fuel cells, and hence focused research in this area is highly desirable. Major issues associated with the successful example of Nafion resulted in the search for alternate proton conducting materials. Even though proton carrier loaded crystalline porous organic frameworks have been used for proton-conduction, the weak host–guest interactions limited their practical use. Herein, we developed a crystalline 2D-polymer composed of benzimidazole units as the integral part, prepared by the condensation of aryl acid and diamine in polyphosphoric acid medium. The imidazole linked-2D-polymer exhibits ultrahigh proton conductivity (3.2 × 10–2 S cm–1) (at 95% relative humidity and 95 °C) in the pristine state, which is highest among the undoped porous organic frameworks so far reported. The present strategy of a crystalline proton-conducting 2D-polymer will lead to the development of new high performing crystalline solid proton conductor.

Derivatization of fullerene (C 60 ) with "branched" aliphatic chains can soften C 60 -based materials and enables the formation of thermotropic liquid crystals as well as room temperature nonvolatile liquids with tunable viscosity. The chain branching methodology with optoelectronic activity of C 60 is believed to be a powerful technique to develop C 60 -based soft and fl exible photovoltaic devices. As featured in:See H. Li et al., J. Mater. Chem. C, 2013, 1, 1943

A summary of the extremely efficient organic phosphors that utilized the best possible ways to manipulate the fate of triplet excitons for achieving a long lifetime along with impressive quantum yield and afterglow properties is provided.