Nowadays, many researchers search methods of making transparent solar cells that can act both as windows and as solar harvesters. Some of them can even be manufactured relatively cheaply using a technology that can spread them onto large areas.
A team of researchers from the Los Alamost National Laboratory and the Brookhaven National Laboratory have recently perfected this type of material.
They made their material as a semiconducting polymer, and used special molecules called “fullerenes” to spike the material. Fullerenes resemble soccer balls and have 60 carbon atoms in their composition. They have the interesting property of self-assembling in a repeating pattern of hexagonal-shaped cells (just like a honeycombs, only micron-sized).
The polymer chains in the material make it transparent, because they pack together at the edges of the hexagon, remaining loosely packed and relatively thin across the centers. The densely packed edges strongly absorb light and could facilitate electrical conductivity, according to the researchers.
“Though such honeycomb-patterned thin films have previously been made using conventional polymers like polystyrene, this is the first report of such a material that blends semiconductors and fullerenes to absorb light and efficiently generate charge and charge separation,” said lead scientist Mircea Cotlet, a Romanian physical chemist at Brookhaven’s Center for Functional Nanomaterials (CFN).
Thin films using this technology were prototyped by the researchers by creating a flow of micron-sized water droplets across a thin layer of the polymer-fullerene solution.
These droplets then self-assembled into honeycomb-like patterns within the polymer solution, leaving only honeycomb-shaped thin film after the water evaporated.
The newly-invented transparent honeycomb solar cell can power new types of displays or can double as power generating windows for buildings. Its cost effectiveness can also encourage solar cell manufacturers to fabricate it massively.