Negative printing by soft lithography.

In inkless microcontact printing (IμCP) by soft lithography, the poly(dimethylsiloxane) (PDMS) stamp transfers uncured polymer to a substrate corresponding to its pattern. The spontaneous diffusion of PDMS oligomers to the surface of the stamp that gives rise to this deleterious side effect has been leveraged to fabricate a variety of devices, such as organic thin film transistors, single-electron devices, and biomolecular chips. Here we report an anomalous observation on a partially cured PDMS stamp where the transfer of oligomers onto Au occurred on regions that were not in contact with the stamp, while the surface in contact with the stamp was pristine with no polymer.

Imaging electroluminescence from individual nanoparticles in an array exhibiting room temperature single electron effect.

Electroluminescence (EL) from the monolayer of a network of a one-dimensional (1D) necklace of 10 nm Au particles (nano)cemented by CdS is imaged. The EL and photoluminescence (PL) spectra confirm the emission from CdS. The EL emission blinks and is highly specular.