Considering the chemistry of the formation and physics at interfaces, we report on the heterostructure of a promising new energy material, Au–Cu2ZnSnS4 (Au-CZTS), and investigate the impact of coupling on Au on improving both the photostability and the photoresponse behavior. We focus primarily on the fundamental issues involved in bringing together two dissimilar materials having different chemical and physical properties in a single building block where one is a multinary semiconductor nanomaterial and the other is a plasmonic noble metal. The formation of heteroepitaxy at the junction of Au and CZTS was investigated for two different phases of CZTS. Considering epitaxy formation along the {111} planes of Au, it was observed that the wurtzite and tetragonal phases of CZTS exhibit coincident site epitaxy with different periodic intervals. A detailed study of this epitaxy formation with Au in both phases of CZTS has been carried out and reported. Because Au-CZTS is a promising new material, we have further investigated its photocurrent and photoresponse behavior and compared them with the properties and behavior of pure CZTS. We believe that these findings will help the energy-materials community, providing guidelines for investigating new functional materials and their applications.

We report the colloidal synthesis of ~3 tungsten-oxygen (W-O) layer thick (~1 nm), two-dimensional (2D) WO 3-x nanoplatelets (NPLs) (x ~ 0.55 Ð 1.03), which display tunable near-infrared localized surface plasmon resonances (LSPR) spectra and high free electron density (N e ) that arises predominantly from their large shape factor. Importantly, the W to O composition ratios inferred from their LSPR measurements show much higher percentage of oxygen vacancies than those determined by X-ray diffraction analysis, suggesting that the aspect ratio of ultrathin WO 3-x NPLs is the key to producing an unprecedentedly large N e , although synthesis temperature is also an independent factor. We find that NPL formation is kinetically controlled, whereas thermodynamic parameter manipulation leads to N e as high as 4.13 X 10 22 cm -3 , which is close to that of plasmonic noble metals, and thus our oxide-based nanostructures can be considered as quasi-metallic. The unique structural properties of 2D nanomaterials along with the high N e of WO 3-x NPLs provide an attractive alternative to plasmonic noble metal nanostructures for energy conversions photochromic nanodevices.

Herein, a facile and effective dilution polymerization route was adopted to prepare microscale hierarchical PANI@BN nanohybrids with a surface textured similar to that of the aloe vera leaf. Synthesized samples were characterized by FTIR, XRD, FESEM, HRTEM, UV−visible absorption, and TGA/DTG. The hydrophobic nanohybrids with extremely rough surface offered a high barrier for moisture and corrosive environments. Potentiodynamic polarization measurement of PANI@BN/ PVA coated steel showed the large shifting in corrosion potential to the anodic region with respect to PANI/PVA. The corrosion inhibition efficiency (IE%) of PANI@ BN/PVA coating on mild steel in 3.5 wt % of NaCl, 1 M HCl, and 1 M H 2 SO 4 was calculated from the respective Tafel plots. The mechanistic investigation of anticorrosion performance was carried out through EIS analysis. The higher IE% of the synthesized nanohybrids with PVA coating formulation indicated that the superior anticorrosion performance on mild steel was due to synergetic effect between PANI and BN nanoparticles.

Fixed-aspect-ratio rod-to-rod conversion of binary V-VI Sb2 Se3 to ternary I-V-VI Cu3 SbSe3 semiconducting nano structures is reported. Capturing the inter mediate products, the insight mechanisms of the ion-diffusion process for the structural transformation are established. The final ternary structure shows localized surface plasmonresonance-induced absorption in the near-infrared regions.

A generic modular synthetic strategy for the fabrication of a series of binary-ternary group II-VI and group I-III-VI coupled semiconductor nano-heterostructures is reported. Using Ag2 Se nanocrystals first as a catalyst and then as sacrificial seeds, four dual semiconductor heterostructures were designed with similar shapes: CdSe-AgInSe2 , CdSe-AgGaSe2 , ZnSe-AgInSe2 , and ZnSe-AgGaSe2 . Among these, dispersive type-II heterostructures are further explored for photocatalytic hydrogen evolution from water and these are observed to be superior catalysts than the binary or ternary semi-conductors. Details of the chemistry of this modular synthesis have been studied and the photophysical processes involved in catalysis are investigated.