A new kind of solar cell could give windows the ability to generate electricity. The polymer solar cells (PSCs), developed by researchers at the University of California, Los Angeles (UCLA) absorb mostly infrared, not visible, light, making them almost 70 percent transparent to the human eye.
The cells are made from a photoactive plastic that converts infrared light into an electrical current, according to an article in ACS Nano that describes the research. Applications could include high-performance, visibly transparent photovoltaic (PV) devices, such as building-integrated PV and integrated PV chargers for portable electronics, said study leader Yang Yang, UCLA professor of materials science and engineering, and director of the Nano Renewable Energy Center at California NanoSystems Institute (CNSI).
A new kind of polymer solar cell that is almost 70 percent transparent to the human eye could give windows the ability to generate electricity by absorbing mostly infrared, not visible, light. (Source: UCLA)
PSCs aren't entirely new, but truly transparent ones are. Previous attempts to make PSCs that are partially or completely transparent to the naked eye have either resulted in devices that are transparent to visible light but not very efficient, or efficient devices that aren't really transparent. The researchers say that this is mostly because the devices were not fabricated with the best combination of polymeric PV materials and efficient transparent conductors. For example, opaque metal electrodes have typically been used.
The UCLA PSCs are lightweight, flexible, and have a maximum transparency of 66 percent at 550nm. They incorporate near-infrared (NIR) photoactive polymer and use a highly transparent silver nanowire-metal oxide composite conducting film as the top transparent electrode. The NIR light-sensitive photoactive polymer balances transparency at visible wavelengths by harvesting solar energy from NIR wavelengths while being less sensitive to visible photons.
The transparent conductor is a major breakthrough, the researchers say. It's made of a mixture of silver nanowire and titanium dioxide nanoparticles. This composite electrode makes it possible for the PSCs to be fabricated in high volume at low cost, via mild solution processes. The transparent PSCs have a power-conversion efficiency of 4 percent.
Other authors of the study are CNSI director Paul S. Weiss; CNSI postdoctoral researcher Yue Bing Zheng; materials science and engineering postdoctoral researcher Rui Zhu; doctoral candidates Chun-Chao Chen, Letian Dou, Choong-Heui Chung, Tze-Bin Song, and Steve Hawks; and Gang Li, former vice president of engineering for Solarmer Energy Inc. The study received funding supported from the Henry Samueli School of Engineering and Applied Science, the Office of Naval Research, and The Kavli Foundation.
Good point, kodaiflow. Like many alternative energy technologies, especially those taking advantage of existing semiconductor infrastructure, the big push has been to make the technology a) work efficiently and b) be manufacturable. I wonder how much LCA studies have been done--that would be really interesting to know, although there may also not be enough data yet.
I think the main question is mean life span. This currently is the largest draw back to PV in it's current form. If these units can produce power for 30 years at a constant level then they justify the investment. The average solar panel that people are rushing to put on their roofs will have a life span (90% of peak) of about 10 years. In that time they may only generate 50% of the energy used to fabricate them.
Mydesign, your impression is incorrect. The US has been experiencing a major economic downturn for several years, including many people losing their jobs and their homes. Also, per capita average income figures are highly misleading, since a given dollar amount often buys much less here than it does in India. Classic examples are the costs for surgery and prescription drugs. In any case, it's a complex picture, especially when making comparisons.
Ann, that’s surprising for me. I though all US citizens are financially well settled peoples. As far as my knowledge, the per capital income of US citizens are more than 10 times of Indian citizens. Through my previous post, I mentioned about the government initiatives for promoting solar energy.
Yes, Ann, that's what I was wondering. I don't know the proper percentages, but say an average high effieciency window block 65% of a certain type of energy (heat, uv, whatever). If the solar cells take out 25% by themselves, that might mean that the cost of the base window could be reduced by eliminating an amount of the doping, and thereby helping to offset some of the cost of the solar cells.
Mydesign, that does resemble some US programs. However, because the cost of installing solar can be around $20,000 (depending on several variables), an often-quoted figure, "only" 40% would be $8,000. Not many people have that amount available for this purpose, even in installments.
Ann, do you know how that compares with your standard high-efficiency home or office window? Just thinking that if this has similar optical properties, there might be a savings in the base cost of the glass that would normally by used (by reducing the amount of "doping chemicals" which would help in the implementation of soemthing like this.
Ann, in the scheme which I mentioned, the upfront cost is only 40% of the total cost and the rest is a subsidy from government, which goes directly to the service provider’s account. So customer has to pay only 40% of total cost, that too in interest free installments (2-6 EMI based on various schemes from different companies).
The 100-percent solar-powered Solar Impulse plane flies on a piloted, cross-country flight this summer over the US as a prelude to the longer, round-the-world flight by its successor aircraft planned for 2015.
GE Aviation expects to chop off about 25 percent of the total 3D printing time of metallic production components for its LEAP Turbofan engine, using in-process inspection. That's pretty amazing, considering how slow additive manufacturing (AM) build times usually are.
For industrial control applications, or even a simple assembly line, that machine can go almost 24/7 without a break. But what happens when the task is a little more complex? That’s where the “smart” machine would come in. The smart machine is one that has some simple (or complex in some cases) processing capability to be able to adapt to changing conditions. Such machines are suited for a host of applications, including automotive, aerospace, defense, medical, computers and electronics, telecommunications, consumer goods, and so on. This radio show will show what’s possible with smart machines, and what tradeoffs need to be made to implement such a solution.