New method for producing ‘Electronic Ink’ — Solar cells as cheap as roof shingles in the near-future?

A new method for producing “electronic ink” — a specialized form of ink from non-toxic nanometer-sized crystals of silicon — has been developed by researchers from the University of Minnesota’s College of Science and Engineering and the National Renewable Energy Laboratory. The researchers say that their new technology brings the possibility of solar-cells-as-cheap-as-roof-shingles one step closer to reality, as well as the means to lower the production costs of a variety of other electronics.

“Imagine a world where every child in a developing country could learn reading and math from a touch pad that costs less than $10 or home solar cells that finally cost less than fossil fuels,” stated Uwe Kortshagen, a University of Minnesota mechanical engineering professor and one of the authors of a new paper detailing the research.
The reason that the electronic ink is so valuable, is that the ‘ink’ can be used to, essentially, “print out” electronics — potentially a much cheaper way to produce many commonly used electronic devices.

“Light is emitted from excited argon gas atoms flowing through the glass tube of a plasma reactor. The plasma is a reactive environment used to produce silicon nanocrystals that can be applied to inexpensive, next-generation electronics.”
Image Credit: University of Minnesota

“This process for producing electronics is almost like screen printing a number on a softball jersey,” stated Lance Wheeler, a University of Minnesota mechanical engineering PhD student and primary author of the new study.
There are still some problems remaining with the process, though, some of which the new research addresses.

The University of Minnesota continues:

First, there is the ubiquitous need of organic “soap-like” molecules, called ligands, that are needed to produce inks with a good shelf life, but these molecules cause detrimental residues in the films after printing. This leads to films with electrical properties too poor for electronic devices. Second, nanoparticles are often deliberately implanted with impurities, a process called “doping,” to enhance their electrical properties.

In this new paper, researchers explain a new method to use an ionized gas, called nonthermal plasma, to not only produce silicon nanocrystals, but also to cover their surfaces with a layer of chlorine atoms. This surface layer of chlorine induces an interaction with many widely used solvents that allows production of stable silicon inks with excellent shelf life without the need for organic ligand molecules. In addition, the researchers discovered that these solvents led to doping of films printed from their silicon inks, which gave them an electrical conductivity 1,000 times larger than un-doped silicon nanoparticle films. The researchers have a provisional patent on their findings.




“What this research means is that we are one step closer to producing more pure and more stable electronic ink with non-toxic chemicals,” Kortshagen stated. “The bigger goal here is to find a way that this research can benefit everyone and make a real difference.”
The work was funded primarily by the Department of Energy Frontier Research Center for Advanced Solar Photophysics.

The new research was just published in the journal Nature Communications.

http://cleantechnica.com/2013/08/02/new-method-for-producing-electronic-ink-solar-cells-as-cheap-as-roof-shingles-in-the-near-future/