Can you really spray on Solar cells?

Back in January 2010 New Energy Technologies unveiled a patent pending process for “spraying” solar panels and their related components onto glass.  The spray concept seemed to catch the publics imagination and of course the idea that you could simply spray from a can onto glass and have a functioning solar window does indeed seem a fantastic breakthrough.  The reality is somewhat different and while the research does indeed show that functional organic layers can be spray coated onto a substrate this is but one step of a multi-phase process to create a fully functional solar panel.

Although the patent applications had been filed a considerable period has to elapse before they become published and available in the public domain.  Earlier this month one of the US patent applications was published and so it is possible to delve a bit deeper into the technology that is being developed.  The research is based on the work of Professor Xiaomei Jiang in the Nanostructure Optoelectronics Lab at the University of South Florida.  New Energy Technologies Inc. are in the process of developing their SolarWindow™ product using this technology.  More recently they have entered into a cooperative Research and Development agreement with the US Department of Energy’s National Renewable Energy Lab. to advance development of SolarWindow™.

The patent application is US20120156825 and summary details are shown below:

Title: Transparent Contacts Organic Solar Panel by Spray

Inventors: Jason Lewis, Jian Zhang, Xiaomei Jiang

Assignee: University of South Florida

Abstract: A method of fabricating organic solar panels with transparent contacts. The method uses a layer-by-layer spray technique to create the anode layer. The method includes placing the substrate on a flat magnet, aligning a magnetic shadow mask over the substrate, applying photoresist to the substrate using spray photolithography, etching the substrate, cleaning the substrate, spin coating a tuning layer on substrate, spin coating an active layer of P3HT/PCBM on the substrate, spray coating the substrate with a modified PEDOT solution, and annealing the substrate.

Claims: The first six claims are worth noting:

1. A method of fabricating organic solar panels with transparent contacts, comprising: applying photoresist to a substrate by spray photolithography; spin coating a tuning layer on the substrate; spin coating an active layer coating on the substrate; spray coating the substrate with a modified PEDOT solution; and annealing the substrate.

2. The method of claim 1, wherein the substrate is an ITO glass substrate.

3. The method of claim 1, wherein the substrate is plastic.

4. The method of claim 1, wherein the substrate is cloth.

5. The method of claim 1, wherein the tuning layer is Cs₂CO₃.

6. The method of claim 1, wherein in the active layer coating is P3HT/PCBM.

There are an additional 17 claims which give further details of the method.

Phil’s comments:  As you can see the concept of simply spraying a solar cell onto glass is a long way from reality.  However, this patent application does explain the technical approach quite well and indicates that the various layers including the contacts are all transparent so that the final result is a solar cell on glass that will still resemble a window.