Quenching of semiconductor quantum dot photoluminescence by a pi-conjugated polymer

In this communication we discuss the possibility of hole transfer between a photoexcited semiconductor quantum dot and a pi-conjugated polymer. This charge-transfer event will be investigated (exploited) on the basis of its implication toward a solar energy conversion scheme. Experimentally, we show that the steady-state photoluminescence (PL) of a solution of InP quantum dots is quenched by the introduction of solvated poly(3-hexylthiophene). Time-resolved PL experiments on these solutions are also presented. It was observed that the PL transients did not significantly change upon the addition of the conductive polymer. These new results indicate that said PL quenching is static in nature. This suggests that in solution, the quantum dot and the polymer exhibit a strong intermolecular interaction. As the two species encounter each other through diffusion, the polymer quenches the quantum dot photoluminescence without altering the population's PL lifetime. This new evidence suggests that the polymer and the quantum dot form a relatively stable complex.     

Wetting of InP by indium- and indium-tin melts

Orientation dependent wetting of InP substrates by In- and In_xSn_1−x melts saturated with InP was studied using the sessile drop method. The contact angle was found to depend on the substrate orientation as follows: It is shown that a tin admixture to the indium melt improves the wetting behaviour. Additional to the dependence on substrate orientation it was found an anisotropic wetting on all investigated faces.