Bottom‐Up Synthesis and Top‐Down Organisation of Semiconductor and Metal Clusters on Surfaces

Abstract

Near-spherical dendrimers can be used as templates for bottom-up syntheses of semiconductor clusters. Starting from methanolic solutions of Cd 2+ , sulfide, and poly(amidoamine) dendrimers, CdS clusters precipitate at the dendrimers. A preparation inside the dendrimers is only possible when the protonation of the latter is carefully controlled. The clusters have diameters above about 2 nm and show blue photoluminescence. The patterning and orientation of CdS/dendrimer clusters on flat surfaces are attained by microcontact printing. Depending on the ripening of the CdS/dendrimer suspension, a sub-micrometer stripe pattern develops inside the micrometer-scaled patterns; it extends over the complete sur-

Electroless synthesis of 3 nm wide alloy nanowires insideTobacco mosaic virus

“…The particles are isolated from plants, wet chemically sensitized/activated with Pd(II) catalyst, and metallized with Co(II) and Fe(II) in suspension. deposition (ELD) can offer an alternative [3,[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. While the ELD of Cu and Ni has been very well investigated since they are employed for various products, many other metals qualify for investigation too [24].…”

“…As in the case of other metallizations we had developed [12][13][14][15][16][17][18] (see also section 4), we first removed unwanted ions such as phosphate from the TMV suspension. The sensitization in Pd(II) required high concentrations of Cl − and H + to produce Pd particles that fit inside the channel, and washing with water to remove surplus Pd(II) (scheme 1).…”

Tobacco mosaic virus: A biological building block for micro/nano/bio systems

“…The exterior surface and/or the central channel of TMV has been selectively metallized using electroless deposition (ELD). [47][48][49][50][51][52][53][54][55][56][57] ELD is advantageous for biological structures since they cannot be contacted electrically; therefore, electrodeposition cannot be utilized. In addition, ELD usually provides uniform coating even on high-aspect ratio structures including nanoscale elements.…”

“…Individual TMV particles can be aligned by a relatively simple processes involving fluid and air flow. 50 In this method, TMV particles in an aqueous solution are oriented by blow-drying of a droplet or by removing a droplet by capillary forces with filter paper. The viruses are aligned in the direction of fluid flow, most likely due to shear forces near the fluid-surface boundary.…”

Hierarchical structures of dendritic polymers

“…Unlike the fan‐shaped dendron, PAMAM dendrimers are not likely to be arranged in stripes because of their symmetric and spherical shapes. However, PAMAM dendrimers can form stripes in films, if they are hybridized with nanoparticles 62. CdS nanoparticles protected by generation four or eight PAMAM dendrimers adsorb onto polydimethylsiloxane (PDMS) substrates, and the morphology of the architecture is stripes of several hundred nanometers in width.…”