For the first time, scientists have found an approach to get polarity and photovoltaic conduct from certain nonphotovoltaic, atomically flat (2D) materials. The key lies in the exceptional manner by which the materials are arranged. The subsequent impact is unique in relation to, and possibly unrivaled to, the photovoltaic impact generally found in solar cells.
Solar power is viewed as a key technology in the move away from fossil fuels. Scientists persistently improve more effective intends to create solar energy. Furthermore, a large number of these developments come from the world of materials research.
Research Associate Toshiya Ideue from the University of Tokyo’s Department of Applied Physics and his team are interested in the photovoltaic properties of 2D materials and their interfaces where these materials meet.
“Quite often, interfaces of multiple 2D materials exhibit different properties to the individual crystals alone,” said Ideue. “We have discovered that two specific materials which ordinarily exhibit no photovoltaic effect do so when stacked in a very particular way.”
The two materials are tungsten selenide (WSe2) and black phosphorus (BP), the two of which have diverse precious crystal structures. Initially, the two materials are nonpolar (don’t have a favored direction of conduction) and don’t create a photocurrent under light.
In any case, Ideue and his team found that by stacking sheets of WSe2 and BP together in the correct manner, the sample showed polarization, and when a light was projected on the material, it created a current.
The impact happens regardless of whether the region of illumination is a long way from the electrodes at one or the flip side of the sample; this is not the same as how the ordinary photovoltaic impact works.
Key to this conduct is the manner in which the WSe2 and BP are aligned. The crystalline structure of BP has reflective, or mirror, symmetry in one plane, while WSe2 has three lines of mirror symmetry.
At the point when the symmetry lines of the materials align, the sample acquires polarity. This sort of layer stacking is delicate work, yet it additionally uncovers to specialists new properties and functions that couldn’t be anticipated just by taking a gander at the ordinary type of the materials.
“The biggest challenge for us will be to find a good combination of 2D materials with higher electric-generation efficiency and also to study the effect of changing the angles of the stacks,” said Ideue. “But it’s so rewarding to discover never-before-seen emergent properties of materials. Hopefully, one day this research could improve solar panels. We would like to explore more unprecedented properties and functionalities in nanomaterials.”
