No abstract

The aim of this study is to quantitatively investigate the effect of different fullerene type (PC 60 BM and PC 70 BM) on various morphological structures and power conversion efficiency (PCE) in the bulk heterojunction (BHJ) P3HT/PC x BM solar cells. The solar cells are fabricated by spin coating without thermal annealing. The quantitative investigations of three-dimensional selforganized nanostructures are performed by using combined grazingincidence small-and wide-angle X-ray scattering technique (GISAXS/GIWAXS). Two types of nanostructures are observed due to the phase separation in the BHJ films during the processing. They include (1) intercalated PC x BM molecules around boundary of P3HT crystalline domain and within amorphous domain and (2) aggregated PC x BM clusters in PC x BM domains. The lamellar spacing of P3HT crystalline domains in P3HT/PC 70 BM is larger than that in P3HT/PC 60 BM. This result indicates more interfacial areas are generated between PC 70 BM and P3HT at the molecular scale for more efficient charge separation. On the other hand, the size, volume fraction, partial attachment, and spatial distribution of PC 60 BM clusters are larger than that of PC 70 BM clusters, which reveals more efficient electron transport in P3HT/PC 60 BM. We deduce the correlation between nanostructures and PCE (3.25% and 2.64%, respectively, for P3HT/ PC 70 BM and P3HT/PC 60 BM). The structure of fullerene intercalated with P3HT rather than the size of fullerene cluster plays a major role in the PCE performance of BHJ solar cell without thermal annealing.

No abstract

We prepared four differently shaped Te nanomaterials (NMs) as antibacterial reagents against Escherichia coli. By controlling the concentrations of hydrazine (N2H4) as reducing agent, NaCl, and temperature, we prepared Te nanowires, nanopencils, nanorices, and nanocubes. These four Te NMs resulted in a live/dead ratio of E. coli cells of less than 0.1, which is smaller than that of Ag nanoparticles. The order of antibacterial activity against E. coli is nanocubes ≈ nanorices > nanopencils ≈ nanowires. This is in good agreement with the concentration order of tellurite (TeO32−) ions released from Te NMs in E. coli cells, revealing that TeO32− ions account for the antibacterial activity of the four Te NMs. We found that spherical Te nanoparticles (32 nm in diameter) with TeO32− ions were formed in the E. coli cells. Compared to Ag nanoparticles that are commonly used as antibacterial reagents, Te NMs have higher antibacterial activity and lower toxicity. Thus, Te NMs hold great practical potential as a new and efficient antibacterial agent.

Carbapenem exposure was associated with emergence of CROPA infections. Repeated carbapenem use in such patients might increase rates of inappropriate initial empirical treatment and mortality. Prudent carbapenem use is important to reduce the emergence of CROPA.