Nanoparticles have been shown in some cases to improve phase separation and morphology in bulk heterojunction organic photovoltaic cells. In this study, the effect of incorporation of polyhedral oligomeric silsesquioxane (POSS) molecules of different structures in air processed poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) films and photovoltaic cells was evaluated. Morphology and composition of the nanoscalephase-separated domains were determined via conductive atomic force microscopy in conjunction with nanomechanical mapping and Raman imaging. UV-vis and fluorescence spectroscopy analysis of the films was performed at different stages of the process and with different levels of solvent vapor and thermal annealing. It was found that POSS molecules of selected structures provided enhancement in morphology control in films, translating to improvements in fill factor and power conversion efficiency of laboratory-scale OPV cells. The findings indicate the potential for further improvements in solar cell performance with specifically tailored POSS/polymer phase-separated systems.

Thermoplastic polyethersulfone (PES) modified multifunctional tetraglycidyl-4,4 0 -diaminodiphenylmethane (TGDDM) and triglycidyl para-aminophenol (TGAP) epoxy prepolymers cured with 4,4 0 -diaminodiphenylsulfone (44DDS) were prepared using a continuous reactor method and their reaction-induced phase separated morphologies and mechanical properties were measured and correlated with chemical compositions. 1 H nuclear magnetic resonance ( 1 H NMR) and near-infrared spectroscopy (NIR) were used to quantify the chemical network formation. Atomic force microscopy (AFM) with nanomechanical mapping was employed to resolve the nanoscale phase-separated morphologies. The extent of phase separation in cured networks and resultant domain sizes were determined to be controllable depending upon the multifunctional epoxy compositions. The results obtained from mechanical studies further indicated that tensile modulus was not largely affected by multifunctional epoxy compositions while fracture toughness increased with increase of TGAP content.

In many studies, search engine data were efficient to analyze and forecast as an explanatory variable, including the tourism volumes predictions. However, the search data and the tourism volumes were always interfered by the noise. Without noise-processing, the predictive ability of search engine data might be weak, even invalid. As a method of noise-processing, Hilbert-Huang Transform (HHT) could deal with non-linear and non-stationary data. This study proposed a model with denoising and forecasting by search engine data, namely CLSI-HHT. The search queries were composited into an index first, then the noise were extracted from the index and tourism volumes sequences by HHT. The study further forecast the tourism volumes with the effective series. The results demonstrated that CLSI-HHT model outperformed the baselines significantly while the index model without denoising performs nearly same as the time series model. Moreover, wavelet transform and filtering were compared with HHT on denoising and the results implied that HHT had higher signal noise ratio (SNR) and forecast more accurately. The study concluded that noise-processing was necessary for the tourism forecasting with search engine data, and HHT could be an effective method on denoising.

Systematically varied annealing, encapsulation, and solvent vapor treatments are conducted to produce stable OPV devices with controlled film morphology and high performance when produced in air. Active layer films are analyzed by AFM, nanomechanical mapping, UV-vis spectroscopy, and XRD. Devices prepared with isopropanol solvent vapor annealing (SVA) combined with thermal annealing (TA) show the highest environmental resistance and performance. Such devices yield average PCE of 3.3%, with stability to atmospheric exposure of up to 60 min prior to encapsulation. Encapsulated devices exposed to the laboratory environment for 30 days exhibit a decrease in PCE of 15%. On application of a second TA step PCE is recovered to over 90% of the original value. The unprecedented air stability of the cells is attributed to the formation of an active layer with a stable, favorable morphology during the SVA process, which is associated with lower oxygen content films.

Effect of substrate temperature and annealing on the structural properties of ZnO ultrafine particle films J. Vac. Sci. Technol. B 15, 805 (1997); 10.1116/1.589413 Investigation of optical and electrical properties of ZnO ultrafine particle films prepared by direct current gas discharge activated reactive method Toluylene 2,4-dicarbamidonitrite ͑TDCN͒ and Ag-ultrafine-particle-TDCN thin films were prepared by using an ionized-cluster-beam ͑ICB͒ deposition method. TDCN is a newly synthesized conjugated polymer with novel properties. These thin films were characterized by transmission electron microscopy ͑TEM͒. The TEM results indicate that the crystalline structure of the organic thin films can be controlled by the parameters of the ICB and the ultrathin crystalline TDCN film can be achieved by using the ICB deposition method. Results also demonstrated that amounts of Ag ultrafine particles embedded in the organic thin films may play an important role in the functional properties of the composite thin films. The electrical bistability of the Ag-ultrafine-particle-TDCN thin films was also achieved, and the possible conductive mechanism of the films was suggested qualitatively.