Transfer printing is one of the key nanofabrication techniques for the large‐scale manufacturing of complex device architectures. It provides a cost‐effective and high‐throughput route for the integration of independently processed materials into spatially tailored architectures.
Furthermore, this method enables the fabrication of flexible and curvilinear devices, paving the way for the fabrication of a new generation of technologies for optics, electronics, and biomedicine. In this work, hydroxypropyl cellulose (HPC) membranes are used as water soluble adhesives for transfer printing processes with improved performance and versatility compared to conventional silicone alternatives. The high‐water solubility and excellent mechanical properties of HPC facilitate transfer printing with high yield for both metal and carbon nanotubes (CNTs) inks. In the case of metal inks, crack‐free stripping of silver films and the simple fabrication of Moiré Plasmonic architectures of different geometries are demonstrated. Furthermore, HPC membranes are used to transfer print carbon nanotube films with different thicknesses and up to 77% transparency in the visible and near infrared region with potential applications as transparent conductive substrates. Finally, the use of prepatterned HPC membranes enables nanoscale patterning of CNT with feature resolution down to 1 µm.
Sustainable energy conversion & storage systems
Hydroxypropyl Cellulose Adhesives for Transfer Printing of Carbon Nanotubes and Metallic Nanostructures
Camilla Dore, Bernhard Dörling, Juan Luis Garcia‐Pomar, Mariano Campoy‐Quiles, Agustín Mihi
The combination of light‐emitting diodes (LEDs) and rare earth (RE) phosphors as color‐converting layers comprises the basis of solid‐state lighting. Indeed, most LED lamps include a photoluminescent coating made of phosphor material, i.e., crystalline matrix suitably doped with RE elements, to produce white light from a blue or ultraviolet LED chip.
At short length scales phonon transport is ballistic: the thermal resistance of semiconductors and insulators is quantized and length independent. At long length scales, on the other hand, transport is diffusive and resistance arises as a result of the scattering processes experienced by phonons. In many cases of interest, however, these two transport regimes coexist. Here we propose a first-principles approach to treat quasiballistic phonon transport where diffusive and ballistic phonons receive separate theoretical treatments.
Superlattices with scattering mechanisms at multiple length scales efficiently scatter phonons at all relevant wavelengths and provide a convenient route to reduce thermal transport. Here, we show, both experimentally and by atomistic simulations, that SiGe superlattices with well-established compositional gradients and a sufficient number of interfaces exhibit extremely low thermal conductivity.
The surprising optical properties of the non-π-conjugated polymer poly(phenylene methylene) (PPM) and its derivatives—that is, absorption in the 350–450 nm and photoluminescence (PL) in the 400–600 nm spectral regions—have been attributed to chromophores formed by homoconjugation along the polymer chain. The enabling role of homoconjugation, however, was hitherto ascertained primarily by excluding alternative origins of luminescence.