Controlling Polarity of Organic Bulk Heterojunction Field-Effect Transistors via Solvent Additives

The effect of additives such as 1,8-diiodooctane (DIO) and 1-chloronaphthalene (CN) on the electronic structures, charge transport and phase separation of small-molecule-based bulk heterojunction (BHJ) films was investigated. Charge transport properties of the BHJ layers significantly changed via the introduction of additives, even though the molecular energy levels remained unchanged. X-ray photoelectron microscopy (XPM) images show the distribution of each phase of the blend films upon the use of additives. The CN additive, in particular, results in a well-percolated network through the active layer

Surface-Modified Wrinkled Mesoporous Nanosilica as an Effective Adsorbent for Benzene, Toluene, Ethylbenzene, and Xylene in Indoor Air

Surfactant-extracted spherical porous silica nanoparticles with wrinkled structures were synthesized, and their adsorption performance was altered by grafting three organosilanes: n-octyltriethoxysilane, hexadecyltrimethoxysilane, and triethoxyphenylsilane onto their surface. The surface-modified silica nanoparticles were used to capture frequently detected hazardous indoor air chemicals. The physical and chemical properties of the samples were characterized using thermogravimetric analysis, Fourier transform infrared spectroscopy, N2 adsorption–desorption experiments, field-emission scanning electron microscopy, and high-resolution transmission electron microscopy. Although the organosilane surface modification did not significantly change the surface areas and pore structures of porous silica nanoparticles, the capacities of the surface-modified porous silica nanoparticles for capturing benzene, toluene, ethylbenzene, and xylene (BTEX) molecules from air were considerably higher than those of pristine porous silica nanoparticles. The dispersion forces between adsorbates and adsorbents were the primary factor that affected the absorption capacity of the surface-modified porous silica nanoparticles. Consequently, the BTEX capturing potential of surface-modified mesoporous silica featuring a long alkyl chain was high because of the relatively high dispersion force between adsorbates and the adsorbent

Observation of Anisotropic Growth and Compositional Discontinuity in AlGaN Electron-Blocking Layers on GaN Microrods

In GaN microrods, phase separation of the AlGaN electron-blocking layer is an enormous obstacle for achieving high-efficiency light-emitting diodes, as this phenomenon negatively affects the device efficiency by inducing unwanted band-energy modulations. Here, we found that the AlGaN electron-blocking layer on each <i>m</i>-plane of the GaN microrod appears to be phase separated, and each electron-blocking layer has a different thickness and length. Our careful analysis based on atom probe tomography reveals that the Al distribution in AlGaN is not uniform and that Al-rich and Al-deficient regions are clearly present. In addition, the longer surface diffusion length of Ga adatoms, as compared to Al adatoms, and the different initial strain state of each <i>m</i>-plane in the GaN rods are deeply associated with the different growth rates and inhomogeneous Al composition of AlGaN, resulting in phase separation of the AlGaN electron-blocking layer. These atomic-scale observations in the structural and chemical composition of AlGaN grown on GaN microrods could provide expanded opportunities for building a wide range of high-quality AlGaN electron-blocking layers

Catalytic Solvolytic and Hydrolytic Degradation of Toxic Methyl Paraoxon with La(catecholate)-Functionalized Porous Organic Polymers

Two robust catechol-functionalized porous organic polymers (catPOPs) with different <i>T</i>_d-directing nodes were synthesized using a cobalt-catalyzed acetylene trimerization (CCAT) strategy. Postsynthesis metallation was readily carried out with La­(acac)₃ to afford catalytically active La-functionalized catPOPs for the solvolytic and hydrolytic degradation of the toxic organophosphate compound methyl paraoxon, a simulant for nerve agents