The great solar conundrum is one that can divide even the greenest of eco-advocates; businesses and homeowners want the clean, affordable commercial energy that comes with solar power, but many don’t want (or can’t have, due to planning regulations) the large photo voltaic cells required to create it.
But what if every window were a solar panel?
That could be the case sooner than we might think, according to a new development at a US-based research facility.
We’ve heard of the idea before – towering buildings turned into huge solar panels by their windows – but many prototypes seem to get stuck at the first hurdle, struggling with efficiency or usability issues such as rapid discolouration.
But Dr Richard Lunt of Michigan State University and his team think they might have a new system capable of going the difference, and turning the buildings of tomorrow into self-sustaining commercial energy producers.
Dr Lunt’s invention harnesses small, organic molecules fine-tuned to capture light that is invisible to the human eye, and encased in luminescent material that is transparent.
“We can tune these materials to pick up just the UV and the near-IR wavelengths that then ‘glow’ at another wavelength in the IR,” explained Dr Lunt, who is the senior author of the paper published in the journal Advanced Optical Materials.
This glowing Infrared light is then guided to the edge of the material – which would be the window frame in practical, commercial application – in which are embedded micro-thin versions of the photovoltaic cells we see on roofs today. As the light ‘glows’, this light can be converted into energy the same way it would in a traditional solar cell.
“Because the materials do not absorb or emit light in the visible spectrum, they look exceptionally transparent to the human eye,” Dr Lunt said.
Current readings only place the efficiency of the current prototype at around 1%, however Lunt says that – with some fine-tuning – his team’s design could top out at around 5%. Whilst still short of the 7% average of similar solar cells, the theory is that the capacity for quantity and the flexibility of the product will compensate for this lower efficiency.
Early predictions seem promising, with the capacity for a wide array of applications both commercially and industrially hoping that there is scope to make the material affordable from day one.
“It opens a lot of area to deploy solar energy in a non-intrusive way. It can be used on tall buildings with lots of windows or any kind of mobile device that demands high aesthetic quality like a phone or e-reader. Ultimately we want to make solar harvesting surfaces that you do not even know are there,” Dr Lunt said.