Graphdiyne, a novel large π-conjugated carbon hole transporting material, is employed as anode buffer layer in colloidal quantum dots solar cells. Power conversion efficiency is notably enhanced to 10.64% from 9.49% compared to relevant reference devices. Hole transfer from the quantum dot solid active layer to the anode can be appreciably enhanced only by using graphdiyne to lower the work function of the colloidal quantum dot solid. It is found that the all-carbon buffer layer prolongs the carrier lifetime, reducing surface recombination on the previously neglected back side of the photovoltaic device. Remarkably, the device also shows high long-term stability in ambient air. The results demonstrate that graphdiyne may have diverse applications in enhancing optoelectronic devices.

Self-assembled functional nanoarchitectures are employed as important nanoscale building blocks for advanced materials and smart miniature devices to fulfill the increasing needs of high materials usage efficiency, low energy consumption, and high-performance devices. One-dimensional (1D) crystalline nanostructures, especially molecule-composed crystalline nanostructures, attract significant attention due to their fascinating infusion structure and functionality which enables the easy tailoring of organic molecules with excellent carrier mobility and crystal stability. In this review, we discuss the recent progress of 1D crystalline self-assembled nanostructures of functional molecules, which include both a small molecule-derived and a polymer-based crystalline nanostructure. The basic principles of the molecular structure design and the process engineering of 1D crystalline nanostructures are also discussed. The molecular building blocks, self-assembly structures, and their applications in optical, electrical, and photoelectrical devices are overviewed and we give a brief outlook on crucial issues that need to be addressed in future research endeavors.

Novel large π-conjugated carbon material, graphdiyne (GD), as a dopant to poly(3-hexylthiophene) (P3HT) hole-transporting material (HTM) layer, is introduced into perovskite solar cells for the first time. Raman spectroscopy and ultraviolet photoelectron spectroscopy measurements reveal that relatively strong π–π stacking interaction occurs between GD particles and P3HT (so-called P3HT/GD composite HTM), favorable for the hole transportation and improvement of the cell performance. On the other hand, some GD aggregates exhibit a scattering nature, and thus help to increase the light absorption of the perovskite solar cells in the long wavelength range. As high as 14.58% light-to-electricity conversion efficiency is achieved, superior to the pristine P3HT-based devices. Additionally, the devices exhibit good stability and reproducibility. Time-resolved photoluminescence decay measurements reveal that the P3HT/GD HTM can accelerate the hole extraction compared with pristine P3HT.

Driven by the association of chemical weak forces and solvent effects, zero- to two-dimensional nanostructures of thiophene-substituted perylene bisimide such as spheres and blocky structures were obtained. Light-controlled intramolecular charge transfer from the trithiophene unit to the perylene bisimide in the solid state can induce a hypochromatic shift and enhanced fluorescent emission.

The construction of efficient synthetic functional receptors with tunable cavities, and the self-organization of guest molecules within these cavities through noncovalent interactions can be challenging. Here we have prepared a double-cavity molecular cup based on hexaethynylbenzene that possesses a highly π-conjugated interior for the binding of electron-rich guests. X-ray crystallography, NMR spectroscopy, UV/Vis spectroscopy, fluorescent spectroscopy, cyclic voltammetry, and SEM were used to investigate the structures and the binding behaviors. The results indicated that the binding of a guest in one cavity would affect the binding of the same or another guest in the other cavity. The effect of electron transfer in this system suggests ample opportunities for tuning the optical and electronic properties of the molecular cup and the encapsulated guest. The encapsulation of different guests would also lead to different aggregate nanostructures, which is a new way to tune their supramolecular architectures.

A novel and facile approach to manipulate the morphology of Cu²⁺-ion-specific assembly of conjugated polymer by coordinative interaction at an oil–water two-phase interface is present. The application of increasing importance is the use of π-conjugated polymers as receptors, exploiting their ability to selectively form complexes, which can obviously change the optical properties in solution and induce the formation of varied solid nano/microstructures. By this method, microtubes are formed through self-rolling of a strained ionic bilayer film at the oil/water interface.

A new supramolecular species of naphthalene-diimide cyclophane containing triazole units was synthesized, and its fluorescent responses to metal ions were investigated in dichloromethane (DCM). The fluorescence emission of NDI was quenched by intramolecular electron transfer, whereas the appearance of dimer emission of the naphthalene-diimide in the presence of Mg²⁺, Ba²⁺, Hg²⁺, Ca²⁺, Zn²⁺ and Pb²⁺ was observed.

The design and synthesis of efficient receptors for tetrahedral oxyanions is an emerging field in supramolecular chemistry. Herein, we have developed a urea-like anion-recognizing motif, amidetriazole, which can be easily synthesized and derived and shows good solubility. A series of simple acyclic receptors were designed and synthesized to confirm the potential of amidetriazole for the construction of tetrahedral oxyanion receptors. This molecular platform can be used extensively for the construction of numerous receptor systems appended with functional groups, which opens the way to many applications in the field of supramolecular chemistry.

Peripheral donor-substituted N,N-dimethyl-4-[(7-nitrobenzo[c][1,2,5]thiadiazol-4-yl)ethynyl]aniline (1a), 4-(benzo[c][1,2,5]thiadiazol-4-ylethynyl)-N,N-dimethylaniline (1b), and 4,4′-{benzo[c][1,2,5]thiadiazole-4,7-diylbis(ethyne-2,1-diyl)}bis(N,N-dimethylaniline) (2) were prepared by Sonogashira cross-coupling reactions. Compounds 1a, 1b, and 2 subsequently reacted with tetracyanoethylene (TCNE) or 7,7,8,8-tetracyanoquinodimethane (TCNQ) to afford the charge-transfer chromophores 3–8. X-ray crystallographic analysis revealed the nonplanarity of these donor–acceptor (D–A) chromophores. Cyclic voltammetry (CV) exhibited a multistep reduction wave. UV/Vis spectra and theoretical calculations identified efficient intramolecular charge-transfer interactions. Moreover, scanning electron microscopy (SEM) showed the morphology transition and reconstruction process of 5 from 0D hollow nanospheres to 1D tubular microstructures.

Two novel cyano-containing oligo(phenylenevinylene) (OPV) derivatives have been designed and synthesized. Photophysical and sensing properties of the two compounds were studied. Such studies reveal the intramolecular charge transfer process between cyano groups and OPV core. The results showed that the alkyl difference of substituted OPV leads to the changes of molecular configuration and metallo-response of two compounds. Copyright © 2010 John Wiley & Sons, Ltd.

The mild and highly efficient thiol-ene click reaction has been used to construct a rotaxane incorporating dibenzo-24-crown-8 (DB24C8) and a dibenzylammonium-derived thread in high yield under the irradiation of UV light. A rotaxane containing a disulfide linkage in the macrocycle was also synthesized by the thiol-ene click reaction. It has been demonstrated that the formation of the [2]rotaxane with the disulfide bond in the macrocycle occurs by a mechanism that is different to the threading-followed-by-stoppering process. The successful construction of a rotaxane directly from its constituent components, the macrocycle containing a disulfide linkage and the dibenzylammonium hexafluorophosphate salt, suggests that the space within the macrocycle incorporating the disulfide linkage is smaller than the phenyl unit and a plausible reaction mechanism has been proposed as follows: A small amount of the initiator forms two radicals upon the absorption of UV irradiation; the radicals act as a “key” to “unlock” the disulfide bond in the macrocycle. The resulting crown ether like moiety in the macrocycle is clipped around the ammonium ion center in the dumb-bell-shaped compound. The [2]rotaxane is generated upon recombination of the disulfide linkage.

Although many cagelike molecules can create a catalytic environment for promoting chemical reactions, the construction of receptors that can host anionic species and sensitize their reaction is novel. Here we report the photochemically induced dimerization of the anion radicals of TCNQ (7,7,8,8-tetracyano-para-quinodimethane) in organic solvent under aerobic conditions when they are encapsulated inside a cationic photoactive receptor. There is clear evidence for a rate increase of over two orders of magnitude, photosensitization of the host, and demonstrated turnover of the catalyst.

The design and fabrication of PTh–PPY heterojunction nanowires that exhibits smart responses to electrochemical redox potentials is described. In their oxidized state, PTh–PPY nanowires act as resistors, whilst in their reduced state, they acts as diodes. Furthermore, the electrical transport mode can be reversibly changed by alternately exposing the nanowires to negative and positive potentials. Constructing full-organic heterojunction nanowires with smart, controllable properties will contribute to the development of intelligent organic devices and organic–electronic circuits on the nanoscale.

Novel organic–inorganic nanonetworks of oligo(phenylenevinylene) (OPV) and gold nanoparticles (GNPs) have been synthesized by the amine-based epoxide ring-opening reaction. The resulting OPV–GNPs nanocomposites exhibit homogeneous and well-defined interfaces between the organic ligands and the inorganic nanoparticles, thereby promoting efficient electronic interfacial interaction between the two constituents. The functionalized gold nanoparticles serve as chemical reagents for the construction of nanohybrids, while the epoxide-terminated OPV acts as linkage between gold nanoparticles. The new architecture provides a facile methodology for fabrication of novel organic–inorganic nanohybrids under relatively mild conditions, which facilitates further applications of hybrid materials.

A solvent driven molecular shuttle that contains a TCBD chromophore and in which the macrocycle can be positioned close to or far from the TCBD unit with a change of solvent is prepared. Several distinct nanostructures are obtained by control of the shuttling movement of the macrocycle: i) in a mixed solvent of CHCl₃/n-C₆H₁₄ (1/1, v/v), the macrocycle locates at the peptide station, and interlaced nanofibers form as a result of the extended intermolecular dipole–dipole interactions of the TCBD units; ii) in a solvent of dimethyl sulfoxide, the macrocycle moves along the long alkyl-chain, and worm-like nanoparticles form because the macrocycle obstructs the intermolecular dipole–dipole interactions of the TCBD units. This system confirms that the molecular aggregation behaviors can be controlled by the shuttling movement of the macrocycle. Exploitation of the molecular shuttle to control the molecular aggregation behaviors will provide greater understanding in the field of molecular shuttle applications.

Two novel multilevel switchable [2]rotaxanes containing an ammonium and a triazole station have been constructed by a Cu^I-catalyzed azide–alkyne cycloaddition reaction. The macrocycle of [2]rotaxane containing a C6-chain bridge between the two hydrogen bonding stations exhibits high selectivity for the ammonium cation in the protonated form. Interestingly, the macrocycle is able to interact with the two recognition stations when the bridge between them is shortened. Upon deprotonation of both [2]rotaxanes, the macrocycle moves towards the triazole recognition site due to the hydrogen-bond interaction between the triazole nitrogen atoms and the amide groups in the macrocycle. Upon addition of chloride anion, the conformation of [2]rotaxane is changed because of the cooperative recognition of the chloride anion by a favorable hydrogen-bond donor from both the macrocycle isophthalamide and thread triazole CH proton.

Solvent driven molecular shuttles containing a pyrene-connected macrocycle and an intramolecular charge-transfer (ICT) chromophore stopper are constructed. In one of the molecular shuttles, a long C-10 chain is introduced in the thread to separate the peptide station and the ICT stopper. The macrocycle stays in the peptide station in apolar solvents and moves to the C10-chain station in highly polar solvents. This moving process alters the electronic interaction between the pyrene unit in the macrocycle and the ICT stopper, which induces the change of the pyrene fluorescence emission. The molecular shuttle exhibits stronger emission when the macrocycle is adjacent to the ICT stopper.

Gold nanoparticles protected by a novel π-conjugated polymer [poly(p-phenylene ethynylene) containing pendent disulfide and bipyridine groups] are synthesized and characterized. The polymer can stabilize the gold nanoparticles effectively. The nonlinear optical properties of the gold nanoparticle colloid solutions in toluene are investigated by using the Z-scan technique at a wavelength of 532 nm and pulse width of 4 ns. The gold-nanoparticle colloid solutions show an exceptional nonlinear absorption effect, which simultaneously contains the saturated absorption resulting from third-order nonlinearity and a large reverse-saturated absorption resulting from fifth-order nonlinearity. In addition, asymmetric self-focusing refractive effects are investigated in the colloid solutions.

A new poly(p-phenylene ethynylene) derivative with pendant 2,2′-bipyridyl groups and glycol units (PPE-bipy) has been prepared, and its metal ion sensing properties were investigated. The polymer of PPE-bipy exhibited high selectivity for Hg²⁺ as compared with Li⁺, Na⁺, K⁺, Ba²⁺, Ca²⁺, Mg²⁺, Al³⁺, Mn²⁺, Ag⁺, Zn²⁺, Pb²⁺, Ni²⁺, Cd²⁺, Cu²⁺, Co,²⁺ and Fe³⁺ in THF/EtOH (1:1, v/v) solution. The fluorescence of PPE-bipy was efficiently quenched by Hg²⁺ ions, and the detection limit was found to be 8.0 nM in a THF/EtOH (1:1, v/v) solvent system. PPE-bipy also showed a selective chromogenic behavior toward Hg²⁺ ions by changing the color of the solution from slight yellow to colorless, which can be detected with the naked eye. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1998–2007, 2008

A series of novel conjugated poly(aryleneethynylene)s (PAEs) co-containing BODIPY have been synthesized and characterized, and their third-order nonlinear optical properties were studied using the Z-scan technique. Interestingly, by introducing the BODIPY skeleton into the PAE backbone, the polymers showed that their nonlinear optical properties were dependent on the BODIPY component. From poly-4 to poly-1, the third-order nonlinear optical properties of the polymers enhanced regularly with the increase of the BODIPY component of the copolymers, indicating that the BODIPY component played decisive roles in enhancing the nonlinear optical properties. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7401–7410, 2008

A novel supramolecular system, which is made up of a dibenzo[24]crown-8 (DB24C8) ring component linked with a calix[4]arene derivative, a dumbbell component, containing a secondary ammonium center (-NR₂H₂⁺-) and a 4,4′-bipyridinium (BIPY²⁺) unit, and stoppered with two 3,5-di-tert-butylphenyl groups on the two termini of the dumbbell component, has been synthesized. The system displays a combination of two processes: the pH-induced shuttling of a DB24C8 ring and the complexation/decomplexation of K⁺ ions. The switching process of this supramolecular system was investigated in detail by ¹H NMR spectroscopy. The results showed that the supramolecular system can only switch smoothly in CD₃CN. The two separated switchable processes can run together smoothly in this supramolecular system.

A [2]rotaxane-based molecular shuttle comprised a macrocycle mechanically interlocked to a chemical “dumbbell” has been prepared in high yields by a thermodynamically controlled, template-induced clipping procedure. This molecular shuttle has two different recognition sites, namely, NH₂⁺ and amide, separated by a phenyl unit. The macrocycle exhibits high selectivity for the NH₂⁺ recognition sites in the protonated form through noncovalent interactions, which include 1) N⁺H⋅⋅⋅O hydrogen bonds; 2) CH⋅⋅⋅O interactions between the CH₂NH₂⁺CH₂ protons on the thread and the oligo(ethylene glycol) unit in the macrocycle; 3) π⋅⋅⋅π stacking interaction between macrocycle and aromatic unit. Upon deprotonation of the [2]rotaxane the macrocycle glides to the amide recognition site due to the hydrogen bonds between the CONH group and the oligo(ethylene glycol) unit in the macrocycle. The deprotonation process requires about 10 equivalents of base (iPr₂NEt) in polar acetone, while the amount of base is only 1.2 equivalents in apolar tetrachloroethane. Upon addition of Li⁺, the conformation of the [2]rotaxane was altered as a result of the collective interactions of 1) hydrogen bonds between pyridine nitrogen and amide hydrogen atoms; 2) coordination between the oligo(ethylene glycol) unit, amide oxygen atom and Li⁺ cation. Then, when Zn²⁺ ions are added, the macrocycle returns to the deprotonated NH recognition site owing to coordination of the macrocycle and NH from the axle with the Zn²⁺ ion. All the above-mentioned movement processes are reversible through the alternate addition of TFA/iPr₂NEt, Li/[12]-crown-4 and Zn²⁺/ethylenediaminetetraacetate (EDTA), by virtue of hydrogen bonding and metal-ion complexation. Significantly, the three independent movement processes are all accompanied by fluorescent responses: 1) complete repression in the protonated form; 2) low-level expression in the deprotonated form; 3) medium-level expression following addition of Li⁺; 4) high-level expression on complexation with Zn²⁺.