A charge-transfer (CT) complex self-assembled from an electron acceptor (NDI-EA: naphthalene diimide with appended diamine) and an electron donor (DAN: phosphonic acid-appended dialkoxynapthalene) in aqueous medium. The aromatic core of the NDI and the structure of DAN1 were designed to optimize the dispersive interactions (π-π and van der Waals interactions) in the DAN1–NDI-EA self-assembly, while the amino groups of NDI also interact with the phosphonic acid of DAN1 via electrostatic forces. This arrangement prevented crystallization and favored the directional growth of 3D flower nanostructures. This molecular geometry that is necessary for charge transfer to occur was further evidenced by using a mismatching DAN2 structure. The flower-shaped assembly was visualized by scanning electron and transmission electron microscopy. The formation of the CT complex was determined by UV-vis and cyclic voltammetry and the photoinduced electron transfer to produce the radical ion pair was examined by femtosecond laser transient absorption spectroscopic measurements.

Graphene nanoplates (GNPs) can be used as a platform for homogeneous distribution of adsorbent nanoparticles to improve electron exchange and ion transport for heavy-metal adsorption. In this study, we report a facile thermal decomposition route to fabricate a graphene-supported Fe–Mg oxide composite. The prepared composite was characterized using scanning electron microscopy, transmission electron microscopy, energy-dispersive spectrometry, X-ray diffraction, and X-ray photoelectron spectroscopy. Batch experiments were carried out to evaluate the arsenic adsorption behavior of the GNP/Fe–Mg oxide composite. Both the Langmuir and Freundlich models were employed to describe the adsorption isotherm, in which the sorption kinetics of the arsenic adsorption process by the composite was found to be pseudo-second-order. Furthermore, the reusability and regeneration of the adsorbent were investigated by an assembled-column filter test. The GNP/Fe–Mg oxide composite exhibited significant fast adsorption of arsenic over a wide range of solution pHs, with exceptional durability and recyclability, which could make this composite a very promising candidate for effective removal of arsenic from aqueous solutions.

Herein, the synthesis and supramolecular self‐assembly of naphthalenediimide (NDI)‐tetraphenylethene (TPE) conjugates with l‐alanine (coded as: 1) and d‐alanine (coded as: 2) was investigated. The pair stereoisomer molecules were designed to undergo self‐assembly under solvophobic effects. Mixtures of THF–water was used to fine tune the solvophobic effect leading to microbelt for both 1 and 2 in 40% v/v of THF in H2O, while microbelt and particulate microsphere supramolecular structures were observed in 20%, v/v THF in H2O. When 10% THF in H2O was employed derivative 1 produces belt‐like structures, however, 2 produces microsphere. Less uniformly defined microstructure morphologies of 1 and 2 were formed in THF/hexane and DCM/hexane. The solvophobic effect on self‐assembly further evidenced using UV/Vis, fluorescence, circular dichroism, X‐ray diffraction (XRD) spectroscopies. DLS used to evaluate formation of assembly in solution, DFT (density functional theory) and TD‐DFT (time dependent density functional theory) molecular modelling support the hypothesis. Scanning electron microscopy used to visualise formation of supramolecular self‐assembled nano‐ and micro‐structures.

Globally recognized for its role as an occupational hazard, carbon dioxide (CO 2 ) detection and monitoring is essential in agriculture, chemical manufacturing, and healthcare/ clinical-oriented applications. Although, optical and chemical gas sensors are available commercially, current gas sensing technologies involving selective monitoring of CO 2 at lower detection limits specifically for industrial conditions still remains a formidable challenge. Herein, we present a simple strategy for highly selective CO 2 detection using an inexpensive transducer platform based on reversible chemisorbed carbonation between CO 2 and CaO-BaTiO 3 heterostructures. Microsensors showed an optimum sensitivity of 65% toward 1000 ppm of CO 2 gas and superior selectivity when operated at 160 °C. Such a remarkable sensing performance originates from the discretely created n-n nanointerfaces and conveniently actualized staggered energy band positions that promote favorable charge transfer upon exposure to CO 2 gas molecules even at parts per million levels. Reversible sensing phenomenon is demonstrated using operando time-resolved diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and correlated with energy band alignment determined from the ultraviolet diffuse reflectance (UV-DRS) spectra to propose the sensing mechanism.

The superior mechanical flexibility, mechanical strength, electrical conductivity, high specific surface area, and a special two-dimensional crystalline structure make graphene a very promising building block material for flexible electromechanical actuators. However, graphene papers have exhibited limited electromechanical actuation strain in aqueous electrolyte solution. In this paper, we show an easy approach to significantly improve the electromechanical actuation of reduced graphene oxide (rGO) papers via fine tuning the oxygen functional groups in rGO sheets, which was achieved by careful control of quantity of the reduction agent used in the chemical reduction process of graphene oxide.The actuation strains are enhanced up to 0.2% at an applied voltage of À1 V, which is more than a 2 fold increase compared to the regular pristine rGO paper. Further theoretical and experimental analyses reveal that the change of the capacitance and the stiffness of the rGO papers are two key factors responsible for the observed improvement.