In recent years, polymer solar cells have drawn considerable research interest due to their attractive features including flexibility, semi-transparency, and manufacturability using cost-effective continuous printing processes. However, one challenge limiting their commercialization is the relatively low power conversion efficiency when compared to inorganic solar cells. New work shows that low bandgap polymer solar cells with high efficiency of 5.5% can be fabricated using nanoimprint lithography.
Researchers have demonstrated that they can print interwoven structures of quantum dots, polymers, metal nanoparticles, etc, to create the first fully 3D printed LEDs, in which every component is 3D printed. At the fundamental level, 3D printing should be entirely capable of creating spatially heterogeneous multi-material structures by dispensing a wide range of material classes with disparate viscosities and functionalities, including semiconducting colloidal nanomaterials, elastomeric matrices, organic polymers, and liquid and solid metals.
Inspired by nature's ingenious biological designs, researchers have persistently attempted to mimic these biofunctionalities to bring technological breakthroughs. One of these morphologies - the unique shape of a helical coil - is not only interesting from a scientific standpoint but also pivotal, offering DNA its distinctive properties and propelling flagella in viscous fluids, to name a few. With the advent of personalized medicine on the horizon, researchers are now trying to use tiny springs made of carbon nanotubes, i.e. nanocoils, to propel nanorobots to perform microsurgeries.
The complexity and high cost of the state-of-the-art high-resolution lithographic systems are prompting unconventional routes for nanoscale manufacturing. Inspired by natural nanomachines, synthetic nanorobots have recently demonstrated remarkable performance and functionality. Nanoengineers now have invented a new nano-patterning approach, named Nanomotor Lithography, which translates the autonomous movement trajectories of nanomotors, or nanorobots, into controlled surface features that brings a twist to conventional static optical fabrication systems.
Researchers have demonstrated ultra-stretchability in monolithic single-crystal silicon. The design is based on an all silicon-based network of hexagonal islands connected through spiral springs. The resulting single-spiral structures can be stretched to a ratio more than 1000%, while remaining below a 1.2% strain. Moreover, these network structures have demonstrated area expansions as high as 30 folds in arrays. This method could provide ultra-stretchable and adaptable electronic systems for distributed network of high-performance macro-electronics especially useful for wearable electronics and bio-integrated devices.
Impurities during the production process of liquid crystal devices result in mobile ions that influence the LCs' field-induced switching phenomena, resulting in a phenomenon called image sticking, or ghosting. Researchers now have developed a method to reduce the presence of excess ions by doping LCDs with ferroelectric nanoparticles. They demonstrate that this reduction of free ions has coherent impacts on the LC's conductivity, rotational viscosity, and electric field-induced nematic switching.
3D-printing processes are engineered to use material more efficiently, give designs more flexibility and produce objects more precisely. These 3D printing techniques are reaching a stage where desired products and structures can be made independent of the complexity of their shapes. Applying 3D printing concepts to nanotechnology could bring similar advantages to nanofabrication - speed, less waste, economic viability - than it is expected to bring to manufacturing technologies. here we show examples of current research into 3D printing in nanotechnology.
Ferroelectric liquid crystal (FLC) display technology holds the promise of fast switching times, a large viewing angle, and high resolution. FLCs have a spontaneous polarization whose direction is perpendicular to the layer. This spontaneous polarization plays an imperative role in the electro-optic switching of FLCs. Researchers have now developed a technique to amplify the spontaneous polarization by doping graphene into FLCs.