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The cathode interlayer (CIL) plays an important role in maximizing the photovoltaic efficiency of polymer solar cells (PSCs). The principle to design organic/polymeric CIL materials is to functionalize π-conjugated skeletons with specific polar/ionic groups. Here, using the principle of organic/polymer CIL materials, we developed graphene quantum dots functionalized with tetramethylammonium at the edge (GQDs-TMA) to be used as a CIL for PSCs with good device performance. The peripheral tetramethylammonium groups can form an interfacial dipole with the cathode to decrease the work function. Graphene quantum dots are used as the π-conjugated skeleton because of their facile synthesis, high conductivity and good film-forming capability. As a result, using an active layer of PCDTBT:PC71BM, a power conversion efficiency (PCE) of 7.01% is achieved with GQDs-TMA as the CIL, much higher than that (

Tensile deformation behavior of amorphous Poly (1,4-cyclohexylenedimethylene Terephthalate) (PCT) at 25 °C–108 °C was investigated by means of in situ synchrotron wide-angle X-ray scattering (WAXS). WAXS patterns were processed in a way that the scatterings from isotropic and anisotropic structures were separated. It turned out that the influences of temperature during deformation can be divided into three zones: below 80 °C, only molecular chains oriented; between 80 °C to 90 °C, very few imperfect crystals were induced by strain; above glass transition temperature (92 °C), the triclinic PCT crystalline structure began to form during deformation process. It was found that the Gaussian model of Haward and Thackray described the stress-strain behavior of the tensile stretched amorphous PCT very well. However, when being stretched above 80 °C, the system showed two characteristic network moduli because of strain-induced crystallization. The onset of change in network modulus occurred immediately after the formation of unoriented crystallites which served as physical cross-linking points to reinforce the material.

With normal organic surfactants, graphene can only be dispersed in water and cannot be dispersed in low-boiling-point organic solvents, which hampers its application in solution-processed organic optoelectronic devices. Herein, we report the exfoliation of graphite into graphene in low-boiling-point organic solvents, for example, methanol and acetone, by using edge-carboxylated graphene quantum dots (ECGQD) as the surfactant. The great capability of ECGQD for graphene dispersion is due to its ultralarge π-conjugated unit that allows tight adhesion on the graphene surface through strong π-π interactions, its edge-carboxylated structure that diminishes the steric effects of the oxygen-containing functional groups on the basal plane of ECGQD, and its abundance of carboxylic acid groups for solubility. The graphene dispersion in methanol enables the application of graphene:ECGQD as a cathode interlayer in polymer solar cells (PSCs). Moreover, the PSC device performance of graphene:ECGQD is better than that of Ca, the state-of-the-art cathode interlayer material.

An efficient “one-pot” route for the synthesis of benzo[4,5]imidazo[2,1-a] isoquinolines has been developed via nucleophilic addition of 2-aryl benzimidazoles to alkynyl bromides and subsequent palladium-catalyzed intramolecular C–H vinylation.

An efficient “one-pot” route for the synthesis of benzo[4,5]imidazo[2,1-a] isoquinolines has been developed via nucleophilic addition of 2-aryl benzimidazoles to alkynyl bromides and subsequent palladium-catalyzed intramolecular C–H vinylation.