Breakthrough Solar Technology - Introducing Spray-on Solar Cells

Imagine being able to capture pure energy from just about any outside surface - a roof, a wall, a building, even a rooftop. That idea doesn't seem so far-fetched, taking into account that solar technology already does exactly that.
However, what if solar energy can be captured from all of these surfaces - roofs, walls, buildings, rooftops - without having huge solar panels installed. What if you can turn any surface into an energy-catching 'sponge', soaking up sunlight and then converting it into electrical energy?

The question we should be asking is not: 'can it be done?' - but rather:'why is it not already being done?'. Sun energy is absorbed into the earth's surface every day, and with such a vast amount of free energy at our disposal, it would be unwise not to make use of this wonderful opportunity. What if an entire building's surface could be designed to act as a 'sponge' to absorb and convert sunlight energy, and then feed it into a central electrical grid? What of you can even turn a window into a solar energy receptor?
The possibility of this idea may not be that far off. Chemical engineer, Brian Korgel, and his team from the University of Texas, in the US, have been working on a suitable solution to reducing solar cell manufacturing costs by as much as 90% of the current cost, and what they have come up with might just revolutionize the entire solar cell industry.
Managing to cut costs to roughly 10 percent of current manufacturing costs, they have come up with what could be described as a type of nanoparticle 'ink'. This 'ink' can be spray-painted onto many surfaces, for example onto the sides of buildings or even glass (using a semi-transparent ink)
He uses light-absorbing nanomaterials that are reportedly about ten thousand times thinner than a strand of hair, and instead of using silicon, they are now using copper indium gallium selenide (CIGS).
This type of technology could very well be ready for commercial use within the next 5 years, maybe even sooner.
In my opinion this is a wonderful concept, and if it can be implemented it would be great. Imagine standing in front of the window in your house or apartment, feeling the sun shining warm on your face, and then realising that the very window you are looking out of, is also at that moment capturing free energy from the sun and converting it into usable energy. Again, what a great concept, in my opinion.