The development of nanoscale electronic and photonic devices will require a combination of the high throughput of lithographic patterning and the high resolution and chemical precision afforded by self-assembly. However, the incorporation of nanomaterials with dimensions of less than 10 nm into functional devices has been hindered by the disparity between their size and the 100 nm feature sizes that can be routinely generated by lithography. Biomolecules offer a bridge between the two size regimes, with sub-10 nm dimensions, synthetic flexibility and a capability for self-recognition. Here, we report the directed assembly of 5-nm gold particles into large-area, spatially ordered, two-dimensional arrays through the site-selective deposition of mesoscopic DNA origami onto lithographically patterned substrates and the precise binding of gold nanocrystals to each DNA structure. We show organization with registry both within an individual DNA template and between components on neighbouring DNA origami, expanding the generality of this method towards many types of patterns and sizes.

High-density arrays of oligonucleotide probes are proving to be powerful new tools for large-scale DNA and RNA sequence analysis. A method for constructing these arrays, using light-directed DNA synthesis with photoactivatable monomers, can currently achieve densities on the order of 10 6 sequences͞cm 2 . One of the challenges facing this technology is to further increase the volume, complexity, and density of sequence information encoded in these arrays. Here we demonstrate a new approach for synthesizing DNA probe arrays that combines standard solid-phase oligonucleotide synthesis with polymeric photoresist films serving as the photoimageable component. This opens the way to exploiting high-resolution imaging materials and processes from the microelectronics industry for the fabrication of DNA probe arrays with substantially higher densities than are currently available.

Articles you may be interested inReal-time Fourier transform infrared spectroscopy study of the kinetics of acid-catalyzed negative-tone resists based on hexamethoxymethylmelamine and phenolic resins Negative electron-beam nanofabrication resist using acid-catalyzed protection of polyphenol provided by phenylcarbinol J.Deep-ultraviolet (UV) chemically amplified (CA) resists are leading candidates for semiconductor lithography manufacturing in the sub-half-micron regime. In this article, we describe in situ, high data rate, accurate measurements of the chemical kinetics that occur in CA resists during the post-exposure bake. The thermal and acid-catalyzed deprotection of two candidate deep-UV resist materials, poly(p-t-butoxycarbonyloxystyrene) (PTBOCST) and poly(t-butylmethacrylate) (PTBMA), was characterized. The thermal deprotection of PTBOCST and PTBMA showed auto-accelerated behavior as the reaction proceeds, while the acid-catalyzed deprotection displayed inhibition as extent of conversion increased. We propose models for the thermal and acid-catalyzed deprotection and extracted rate coefficients using a stochastic kinetics simulator. Excellent agreement between the model and experimental data was obtained.

We have synthesized a series of diphenylamine-substituted coumarin, (dicyanomethylene)pyran, and benzophenoxazone dyes and report on their optical and electroluminescent properties, thermal and photooxidative stabilities, and potential as red and green dopants for organic light-emitting diode (OLED) displays or down-conversion fluorescent dyes for external color-converters. Incorporation of the bulky phenyl groups in these dyes delays the onset of concentration quenching when they are dissolved in polymer films. Their improved photoluminescent efficiency and photooxidative stability make them excellent candidates for external color-conversion. The improved electroluminescence and power efficiencies and enhanced thermal stability of 3-(2‘-benzimidazolyl)-7-(diphenylamino)-2H-1-benzopyran-2-one (C7S) as well as its Commission Internationale d'Eclairage (CIE) coordinates suggests its use as a green dopant in OLED devices.

For adequate transparency we have selected hexafluoroisopropanol as an acid group and an ␣-trifluoromethylacrylic moiety as a repeat unit of our 157 nm resist polymers. The hexafluoroalcohol group is bound to norbornene or styrene. Four platforms are currently available to us: ͑1͒ all-acrylic, ͑2͒ all-alicyclic, ͑3͒ acrylic-alicyclic, and ͑4͒ acrylic-aromatic systems. While the all-alicyclic ͑all-norbornene͒ polymers are synthesized by transition-metal-initiated addition polymerization, all other polymers involving ␣-trifluoromethylacrylic monomers are prepared by conventional radical copolymerization. Characterization of the polymers and preliminary lithographic evaluation are reported.

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