Bulk-heterojunction organic photovoltaic (BHJ-OPV) technology promises high efficiency at ultralow cost and weight, with potential for nontraditional applications such as building-integrated photovoltaic (PV). There is a widespread presumption that the complexity of morphology makes carrier transport in OPV irreducibly complicated and, possibly, beyond predictive modeling. However, understanding the complex morphology is important because it not only dictates cell efficiency but also the panel performance and the operating lifetime. In this paper, we derive the fundamental thermodynamic as well as morphology-specific practical limits of BHJ-OPV efficiency and lifetime. We find that performance improvement relies not only on morphology engineering but also on increasing the effective mobility–lifetime (μτ) product, the cross-gap between donor/acceptors, and reducing the series resistance. Even if the OPV fails to achieve the highest efficiency anticipated by the thermodynamic limit, its novel form factor, lightweight, and transparency can make it a commercially viable option for many applications.

Density functional theory, which can be used for simulating the properties of materials in the electronic ground state, was extended to time-dependent density functional theory (TDDFT). This extension enabled us to simulate nonthermal (nonequilibrium) dynamics under electronic excitation as well as to analyze and predict phenomena observed in experiments using femtosecond lasers. In this invited paper, a numerical simulation based on TDDFT for laser-induced dynamics of molecules encapsulated in carbon nanotubes (CNTs) is presented. Fast motion of molecules can be induced by short strong laser pulses that cause electronic excitation. The role of CNTs is not simply trapping the molecules but also modulating the electric field of the laser pulse. This knowledge of microscopic-scale processes will be useful when using CNTs as nanoscale test tubes in future photochemistry experiments in confined spaces for the synthesis of exotic materials. The numerical scheme and detailed results of the simulation are also presented here.

Within the last decade, inkjet printing technology has developed from only a text and graphic industry to a major topic of scientific research and development. Inkjet printing can be used as a highly reproducible noncontact patterning technique to print at high speeds either small or large areas with high quality features; it requires only small amounts of functional materials, which immediately lower production costs. Furthermore, inkjet printing reduces the amount of processing steps due to its additive technique of materials deposition, which further decreases productions costs. This contribution provides a literature survey covering the latest results in low temperature sintering inkjet-printed metal precursor materials in a fast and efficient manner, aiming for roll-to-roll processing. The prepared features can be used as interconnects and contacts for microelectronic applications, including organic light-emitting diodes, organic photovoltaics, and radio frequency identification tags.

The review describes the workflow of a high-throughput screening process for the rapid identification of new and improved gas sensor materials. Multiple nanoparticulate metal oxides were synthesized via the polyol method, and material diversity was achieved by volume and/or surface doping. The resulting materials were applied as thick films on multielectrode substrates to serve as chemiresistors. This high-throughput approach including automated preparation, complex impedance measurements, and evaluation procedures enables reproducible measurements and their visual representation. Selected examples demonstrate the state of the art for applying high-throughput impedance spectroscopy in search of new sensitive and selective gas sensing materials as well as in analyzing structure–property relations.

Storage is the main problem to use hydrogen as a fuel in the car industry. Porous carbons are promising storage materials. We have performed computer simulations to investigate carbide-derived porous carbons, showing that these materials exhibit a structure of connected pores with graphitic walls. We then apply a thermodynamic model to evaluate the hydrogen storage. The model accounts for the quantum effects of the motion of the molecules in the pores. The pore widths optimizing the storage depend on pore shape, temperature, and pressure. At 300 K and 10 MPa, the optimal widths lie in the range 6–10 Å. The predictions are consistent with experiment. The calculated storage capacities fall below the targets proposed by the U.S. Department of Energy. This is a consequence of the weak interaction between hydrogen and the pore walls. Metallic doping enhances the binding energy of hydrogen to the walls, which has promising consequences for hydrogen storage.

Activated carbon adsorbents with superhigh specific surface areas (SHACs), which are used as adsorbents, were prepared by chemical activation of petroleum coke with potassium hydroxide. We investigated the influence of specific surface area on hydrogen desorption capacity using SHACs with the same pore size distribution, whereas the effect of pore size distribution on hydrogen desorption capacity was studied using SHACs with same specific surface area. Results revealed that hydrogen desorption capacity (N) increased with higher specific surface area (S) of SHAC adsorbents, according to the linear relation: N = k·S + b (k > 0). At 273 K and 9.0 MPa, hydrogen desorption capacity of 20.96 mmol/g (4.02 wt%) was observed on a SHAC adsorbent with a specific surface area of 3348 m2/g. There was a linear relationship between hydrogen desorption capacity and mesopore percentage in SHAC adsorbents, described as: N = k2·Xmic + b (k2 > 0). Hydrogen desorption per unit mesopore surface amounted to 0.72 mmol/m2.

Due to its excellent physical properties, graphene acting as reinforcing fillers has attracted intense interests. To achieve a controlled distribution, the formation of a conductive network composed of graphene sheets within polymer matrix is of critical importance. In this work, polystyrene (PS) microspheres wrapped by graphene oxide (GO) sheets were prepared via layer-by-layer (LBL) assembly of oppositely charged GO sheets onto PS microspheres. The deposited GO was then reduced, and the composite films with a graphene conductive network were prepared by hot pressing. The morphology of graphene conductive network was studied, and the thermal and electrical properties of the composite films were measured. The as-prepared composites showed an improved thermal stability as well as electrical conductivity with a percolation threshold as low as 0.2 vol%. The combination of latex technology and LBL self-assembly method thus demonstrated an efficient and facile approach to fabricate electrically conductive graphene/polymer composites.

There have been efforts to develop alternative transparent conductors to replace indium tin oxide (ITO). A hybrid transparent conductor that integrates a metallic Cu grid and graphene film promises to be a suitable candidate. Flexibility, sheet resistance, and transmittance comparable to ITO have been demonstrated. Here, we show that the optical and electrical properties of the hybrid transparent conductor can be easily tuned by clever design of the metal grid. The outcome of our study provides unprecedented guidelines for future design of metal grids integrated in transparent conductors. We also find that the graphene film forms an effective barrier to retard the degradation of the copper grid when the hybrid transparent conductor is heated in air up to high temperatures for an extended period of time. Hence, a superior hybrid transparent conductor, which can be carefully engineered to display desirable properties, has been demonstrated.

Vanadium oxide nanorods (VONRs) and vanadium oxide nanotubes (VONTs) were fabricated by hydrothermal method with the induction of hydroxyl and carboxyl functionalized carbon nanotubes (CNTs). The functionalized CNTs not only facilitate the dispersion of CNTs but also serve as centers for polymerization in the hydrothermal reaction. The formation of (VONRs) and (VONTs) was observed by field emission scanning electron microscopy, transmission electron microscopy, x-ray powder diffraction and Fourier transform infrared spectroscopy tests. Self-assembling nanotubes and nanorods were formed together with the layered structures, but they followed different formation mechanisms. The “Rolling” and “Attaching-Oriented Attachment Growth” mechanisms are proposed to describe the formation of VONRs and VONTs, respectively.

Structured lead zirconium titanate (PZT)–epoxy composites are prepared by dielectrophoresis. The piezoelectric and dielectric properties of the composites as a function of PZT volume fraction are investigated and compared with the corresponding unstructured composites. The effect of poling voltage on piezoelectric properties of the composites is studied for various volume fractions of PZT composites. The experimentally observed piezoelectric and dielectric properties have been compared with theoretical models. Dielectrophoretically structured composites exhibit higher piezoelectric voltage coefficients compared to 0–3 composites. Structured composites with 0.1 volume fraction of PZT have the highest piezoelectric voltage coefficient. The flexural strength and bending modulus of the structured and random composites were analyzed using three-point bending tests.

Patterned porous films prepared by the breath figure method have received considerable interests because of the potential applications. This paper reports a top–down method to fabricate functional patterned films. Cross-linked polystyrene microspheres were synthesized by a two-stage dispersion polymerization using divinylbenzene (DVB) and ethylene glycol dimethacrylate (EGDMA) as cross-linkers, which provide free vinyl groups on the microspheres surface. The amounts of residual vinyl groups were determined by potentiometric titration. Glucose was then bound to the microspheres via thiol–ene reaction, which was confirmed by x-ray photoelectron spectroscopy and water contact angle measurements. Results indicate that vinyl groups of EGDMA show relatively higher reactivity than that of DVB. Microspheres with glucose were assembled into the pores of honeycomb films prepared by the breath figure method, forming functional arrays for recognizing a lectin, Con A. This top–down method is useful in preparing patterned films with various functional moieties, which may act as a platform, such as, for investigating carbohydrate–lectin interactions and for sensing.

The removal of oil spills or oily organic solvents from water surface is a great technological challenge for environmental protection. Here, a facile method to prepare superhydrophobic and superoleophilic sponge for fast and selective removal of oils from water surface has been reported. The as-prepared sponge exhibited superhydrophobic property with the water contact angle around 165°, which can be used for the absorption of oil spills or oily organic solvents. Furthermore, the resultant sponge showed good durability toward temperature. This fabrication technique is easy to grasp and to be extended. So we believe that this new functionalized sponge could be realized for the large-scale commercialized production.