Category Technology/Electronics

A low viscosity, low boiling point, clean solvent system for the rapid crystallisation of highly specular perovskite films

Scientists at Oxford University have developed a solvent system with reduced toxicity that can be used in the manufacture of perovskite solar cells, clearing one of the barriers to the commercialisation of a technology that promises to revolutionise the solar industry. Perovskites – a family of materials with the crystal structure of calcium titanate – have been described as a ‘wonder material’ and shown to be almost as efficient as silicon in harnessing solar energy, and is significantly cheaper to produce.

By combining methylamine and acetonitrile, researchers have developed a clean solvent with a low boiling point and low viscosity that quickly crystallises perovski...

An illustration of refraction through a normal optical medium versus what it would look like for a medium capable of negative refraction. —Photo courtesy of Cory Dean

Engineers have directly observed for the first time negative refraction for electrons passing across a boundary between 2 regions in a conducting material. First predicted in 2007, this effect has been difficult to confirm experimentally. The electrons in the atomically thin material behave like light rays, which can be manipulated by such optical devices as lenses and prisms. The findings could lead to the development of new types of electron switches, based on principles of optics rather than electronics.

“The ability to manipulate electrons in a conducting material like light rays opens up entirely new ways of thinking a...

SEM – model of a metallic nano-network with periodic arrangement ( left) and visual representation of a fractal pattern (right). Credit: M. Giersig/HZB

HZB scientist Prof. Michael Giersig has recently demonstrated for these applications that networks of metallic mesh possessing fractal-like nano-features surpass other metallic networks in utility. These findings have now been published in the most recent edition of the journal Nature Communications.

Their new development is based on what is termed quasi-fractal nano-features. These structures have similarities to the hierarchical networks of veins in leaves. Giersig’s team was able to show that metallic networks with these features optimise performance of electrodes for several applications...

A chemical design strategy for creating artificial multiferroics using oxide nanosheets. Credit: NIMS

Multiferroics are expected to play a vital role in the development of next-generation multifunctional electronic devices. The design of new multiferroics, or materials that display both ferroelectricity and ferromagnetism, is of fundamental importance for new electronic technologies. However, the co-existence of ferroelectricity and magnetic order at room temperature in single compounds is rare, and heterostructures with such multiferroic properties have only been made with complex techniques (such as pulsed-laser deposition and molecular beam epitaxy).

Seeking to develop room-temperature multiferroics, the research group utilized a new chemical design for artificial multiferroic thin film...