Detailed insights into the formation pathway of CdS and ZnS in solution: a multi-modal in situ characterisation approach.

The high stability, high availability, and wide size-dependent bandgap energy of sulphidic semiconductor nanoparticles (NPs) render them promising for applications in optoelectronic devices and solar cells. However, the tunability of their optical properties depends on the strict control of their crystal structure and crystallisation process. Herein, we studied the structural evolution during the formation of CdS and ZnS in solution by combining in situ luminescence spectroscopy, synchrotron-based X-ray diffraction (XRD) and pair distribution function (PDF) analyses for the first time. The influence of precursor type, concentration, temperature and heating program on the product formation and on the bandgap or trap emission were investigated in detail. In summary, for CdS, single-source precursor (SSP) polyol strategies using the dichlorobis(thiourea)cadmium(II) complex and double-source precursor approaches combining Cd(CH3COO)2·2H2O and thiourea led to the straightforward product at 100 °C, while the catena((m2-acetato-O,O')-(acetate-O,O')-(m2-thiourea)-cadmium) complex was formed at 25 and 80 °C. For ZnS, the reaction between Zn(CH3COO)2·2H2O and thiourea at 100 °C led to the product formation after the crystallisation and dissolution of an unknown intermediate. At 180 °C, besides an unknown phase, the acetato-bis(thiourea)-zinc(II) complex was also detected as a reaction intermediate. The formation of such reaction intermediates, which generally remain undetected applying only ex situ characterisation approaches, reinforce the importance of in situ analysis for promoting the advance on the production of tailored semiconductor materials.

[Elimination kinetics following repeated administrations of chemotherapeutic agents]. / Eliminationskinetik bei wiederholter Applikation von Chemotherapeutica.

Repeated administrations of the chemotherapeutic agents nalidixic acid, retacillin, oxacillin, ampicillin and gentamicin acts on the transport of organic acids by the kidney. With the exception of nalidixic acid, all the chemotherapeutic agents under study produced a significant dose-dependent increase in the renal clearance of p-aminohippuric acid (PAH) in adult rats aged 55 days. Due to nephrotoxic effects, the renal clearance of PAH is decreased by very high doses of nalidixic acid and gentamicin. In contrast to this, the changes in PAH clearance were less marked in 10-day-old rats in which the ability of the kidney to transport organic acids is low. On repeated administrations of chemotherapeutic agents, one has on principle to consider the production of a diminishing effect due to increased renal clearance.