Antimony sulfide as a cost-effective, low-toxic, and earth-abundant solar cell absorber with the desired bandgap was successfully deposited using a scalable close space sublimation technique. The deposition process can separately control the substrate and source temperature with better engineering of the absorber quality. The device performance can reach 3.8% with the configuration of glass/FTO/CdS/Sb2S3/graphite back contact. The defect formation energy and the corresponding transition levels were investigated in detail using theoretical calculations. Our results suggest that Sb2S3 exhibits intrinsic p-type owing to S-on-Sb antisites (SSb) and the device performance is limited by the S vacancies. The localized conduction characterization at nanoscale shows that the non-cubic Sb2S3 has conductive grains and benign grain boundaries. The study of the defects, microstructure, and nanoscale conduction behavior suggests that Sb2S3 could be a promising photovoltaic candidate for scalable manufacturing.

Bismuth telluride (Bi2Te3) two-dimensional (2D) nanosheets prepared by van der Waals epitaxy were successfully detached, transferred, and suspended for nano-indentation measurements to be performed on freestanding circular nanosheets. The Young's modulus acquired by fitting linear elastic behaviors of 26 samples (thickness: 5-14 nm) is only 11.7-25.7 GPa, significantly smaller than the bulk in-plane Young's modulus (50-55 GPa). Compliant and robust Bi2Te3 2D nanosheets suggest the feasibility of the elastic strain engineering of topological surface states.

With the increasing demand for highly efficient and durable catalysts, researchers have been doing extensive research to engineer the shape, size, and even phase (e.g., hcp or fcc Co) of individual catalyst nanoparticles, as well as the interface structure between the catalyst and support. In this work, cobalt oxides were deposited on ceria with rod-like morphology (CeO2NR) and cube-like morphology (CeO2NC) and silica with sphere-like morphology (SiO2NS) via a precipitation–deposition method to investigate the effects of support morphology, surface defects, support reducibility, and the metal–support interactions on redox and catalytic properties. XRD, Raman, XPS, BET, H2-TPR, O2-TPD, CO-TPD, TEM, and TPR/TPO cycling measurements have been mainly employed for catalysts characterization. Compared with CeO2NC and SiO2NS supports, as well as CeO2NC- and SiO2NS-supported cobalt catalysts, CeO2NR counterparts exhibited enhanced reducibility and CO oxidation performance at a lower temperature. Both the apparent activation energy and CO conversion demonstrated the following catalytic activity order: 10 wt % CoO x /CeO2NR > 10 wt % CoO x /CeO2NC > 10 wt % CoO x /SiO2NS. These results showed a strong support-dependent reducibility, CO oxidation, and redox cycling activity/stability of the as-prepared catalysts. Moreover, the significantly enhanced catalytic CO oxidation of the 10 wt % CoO x /CeO2NR catalyst indicated the vital role of CeO2NR support with rich surface oxygen vacancies, superior oxygen storage capacity and mobility, and excellent adsorption/desorption behavior of CO and O2 species.

The first step in synthesizing a model film morphology via a surface-driven hierarchical assembly process is presented. The goal of the hierarchical assembly is the control of the morphology of complex molecular layers for the investigation of fundamental processes in organic solar cells. Using a focused ion beam (FIB) with Ga+ ions at 30 keV, the surface of highly oriented pyrolitic graphite (HOPG) is patterned with an array of local amorphous carbon ellipsoid spots (ACES), which provide preferential nucleation lines at their perimeter, and thus are instrumental in the control of fullerene island growth. On the undamaged surface regions outside the ACES pattern the fullerene island growth is unperturbed, and presents the well-known combination of round and fractal island shapes. The fullerene deposition at the periphery of the ACES pattern, which is characterized by single ion impact defects, results in stunted, smaller and irregular islands. Inside the ACES array, the C60 island growth is controlled by the shape of the ACES and is constrained to lobes which form around each ACES spot. The array and C60 lobe morphology and geometry are characterized and a subsequent understanding of the C60 diffusion fields and nucleation lines within the array is discussed.