Thought this was interesting and just passing it along given all the interest in solar companies. The study was conducted by the University of Maryland:
Scientists have designed a novel type of nanoscale solar cell. Initial studies and computer modelling predict these cells will outperform traditional solar panels, reach power conversion levels by over 40 percent.
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To investigate what is possible in terms of solar power, the researchers have examined the Shockley-Queisser limit for different materials. This equation describes the maximum solar energy conversion efficiency achievable for a particular material, allowing different materials to be compared as candidates for power generation.
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The scientists have produced a single-junction nanostructured solar cell. This type of solar cell appears to have an efficiency rating of 42 percent. While this may not sound like much, in terms of power utilization it is very significant.
This new technology could revolutionize the solar industry by allowing for significantly more power generation from a single device by simply making it much smaller…
discussing efficiency of various types of solar cells. Notable is the loss to heat. Too bad that can’t be captured but solar does not work at high temps.
So most of the sun energy is wasted.
As is most of the energy from fossil fuel being burned in a power station. The big difference is that the sunlight is free, we don’t have to pay for the sun 's fusion reaction. Which becomes an ever bigger factor as fossil hydrocarbons get ever harder and more expensive to find. Over the next decade this is not predictable but over the next 5 or 10 decades it is.
Notable is the loss to heat. Too bad that can’t be captured but solar does not work at high temps.
There is study and experimentation down that path. It is not out of the labs yet. Mostly it is about up converting and down converting infra-red and ultra violet to the spectrum that can be captured. The heat problem is mitigated that way.
Solar labs at universities and research institutes are working on cool stuff that is typically twice as efficient as the most efficient solar panels on the market, but the path to commercialization is hard.
An analogy from my field–biology. Killing cancer in a petri dish is easy–most undergrads can discover new cancer-killing substances rather easily. However, that is a long way from creating commercially-available cancer drugs.
Matt,
I worked part time on developing solar cells starting in 2005, quit my day job in 2007 to design nanoscale solar cells, filed numerous patents, and founded a solar company (no I am not making this up) that I worked in until 2010. I was the last founder who worked in the company. I’m not working with them for reasons I won’t go into. Suffice it to say, I am interested in solar technology and articles covering technology like this is not particularly new. There are several things that you should look at when evaluating technology:
Efficiency of the solar cell or peak conversion which is defined as the amount of solar power using one sun (i.e. 1000 W/m^2 of light approximating the sun’s spectrum). 40% efficiency = 400 W/m^2.
How much energy is produced per day. That’s where my team’s solar cells shine ;o) I think the technology of my company is at least double that of planar cells, but I don’t have access to the hard data so that is only a SWAG.
How sturdy are the solar cells. This sounds like a minor thing, but over the ~20 year life, some solar cells will be hit with hail. Some processes (last I checked this was the case with First Solar) heat glass and weaken it.
Is is economic to manufacture defect free solar cells? I wish I knew how my company is doing in this department. Unfortunately, they are choosing to be tight lipped.
How hot does the solar cell run. Solar cells are like a pachinko machine. If the electrons make it all the to the bottom, you win some electricity. If the electrons fall into a hole, you get heat that will reduce the efficiency of the cell. That heat will gradually degrade the performance of the solar cell by causing defects in the P-N junction.
My point is that there is a LOT that goes into photovoltaic technology. It IS getting better all of the time, but there are and always will be technical hurdles that need to be overcome.
One of the more interesting applications for high-efficiency solar cells is electric cars. 5 square meters of such high-efficiency solar cells could greatly increase the range. An hour parked in the sun would give maybe an additional 15 miles of range, depending on the level of solar irradiance.
5. How hot does the solar cell run. Solar cells are like a pachinko machine. If the electrons make it all the to the bottom, you win some electricity. If the electrons fall into a hole, you get heat that will reduce the efficiency of the cell. That heat will gradually degrade the performance of the solar cell by causing defects in the P-N junction.
bulwnkl,
Thanks very much for that summary. I have one tiny follow-up question. Given that I’m hoping to retire to a tropical area within a few years and plan to install both solar electric and solar water heating (most people in that are just take cold showers because of the warm weather, but I’m a spoiled baby a question hits me:
I’m wondering if anybody is designing panels to pull off the excess heat from photo-voltaics and using it for water heating purposes? That would seem to provide a beneficial use of a negative byproduct, the way that you’ve described it.
as always, i am full of carp
(First post on these boards after lurking for a couple of months.)
400 watts per square meter (from the earlier post), with the 5 square meters proposed, is 2000 watts, or 2 kilowatts. In an hour that would ge 2 KWh. A quick Google* gave 3.5 miles per kWh, so that is seven miles… IF 5 square meters of state-of-the-art cells were presented to the sun for ideal solar input. I don’t see where 5 square meters of solar cells could be put on a car and all point at the sun, but maybe I lack imagination.
1. Efficiency of the solar cell or peak conversion which is defined as the amount of solar power using one sun (i.e. 1000 W/m^2 of light approximating the sun’s spectrum). 40% efficiency = 400 W/m^2.
I suspected that might be noon in the tropics.
But I don’t know. I understand elevation makes a huge difference also.
Full Of Carp,
To answer your question, I have not seen a serious attempt at that. A big part of having integrity in a solar cell is to have a weather resistant seal like EVA. If water and dirt make there way into a cell, defects can happen in many different ways. Trace elements you need for your solar cell to work for 20 years could diffuse or leach out, but before you could damage the cell that way, you would likely short it out. When I built my first prototypes, I didn’t have a conductive glass layer (transparent conductive oxide) as is the usual case. What I did do is put a droplet of water on my 1 cm x 1 cm solar cell. I got a cell lifetime of anywhere between 5 and 10 minutes :o) Just so you know, we were down to our last 5 parts that were 1 cm x 1 cm. Angel funding ran out. Family savings just about to run out. 5-10 minutes was not long enough for a lab made (almost garage like conditions) developmental solar cell to the hit the market. However, the efficiency was so high, we were able to raise $10MM dollars for my company.
a question hits me: