Questions tagged [solar-cells]
262 questions
62
votes
11 answers
Why don't solar panels contribute to global warming?
I've been wondering this for a while but I have not yet encountered an explanation.
This is from my understanding of physics, which is by no means expert, so sorry for my crude explanation:
Energy within earth can be considered a closed system; it…
Joeri Hendrickx
- 731
56
votes
1 answer
Do solar panels get less hot than objects of a similar color?
If you put a flat, dark object out in the sun, it gets hot. This happens because the object absorbs light and converts it into heat. However solar panels instead convert some incident light into electricity, with efficiencies sometimes approaching…
user34722
- 3,303
38
votes
4 answers
Why are solar panels kept tilted?
I have noticed that, in my country India, most of the solar panels are tilted southward at an angle of ${45}^{\circ} .$ Even on buildings with inverted V-shaped roofs, solar panels are still oriented southward on both the sides of…
Chemist
- 591
33
votes
3 answers
Is plant photosynthesis more efficient than solar panels?
Is photosynthesis more efficient than solar panels? If so, by how much?
Chris Laforet
- 2,535
30
votes
7 answers
Why is silicon used for making solar cells?
Silicon has a bandgap of 1.1 eV, whereas germanium has 0.65 eV. Silicon has an indirect bandgap, whereas gallium arsenide has a direct bandgap. Still silicon is mainly used for making solar cells. Why?
Wonder
- 762
23
votes
2 answers
Where does electricity go from a solar panel that is not plugged in to anything?
I found a similar question here on this site, but my question is slightly different. If a solar panel is exposed to sunlight but is not plugged in to anything--dc load, inverter, etc--where does that electricity go? In this example, I'm assuming the…
Zachary
- 231
14
votes
5 answers
Where does the electricity, generated by a solar panel, go if you don't use the electricity?
I'm sorry if this question is too trivial for this Q&A forum. I am a layman when it comes to physics (though I did cover the high-school physics courses).
I was wondering what happens to the electricity, that is generated by your own solar panel, in…
Max Lonysa Muller
- 1,083
13
votes
3 answers
What is different in the morning sunlight so it doesn't produce as much electricity as at noon?
Consider I have a solar panel setup as in the above picture. The top sketch is sketching sun rays in the early morning around 6 AM in a clear bright sky. The bottom sketch is sketching the sun ray hitting the solar panel at around 8 AM.
I installed…
AirCraft Lover
- 263
10
votes
1 answer
What kind of engine is a photovoltaic solar cell?
I have read several times here (on PSE) and there (in Google) that photovoltaic solar cells aren't heat engines. I.e. they are not working via a heat transfer between 2 reservoirs, and so they are not limited by Carnot efficiency. Ok, very good, but…
9
votes
1 answer
Will the upcoming solar eclipse stress the European electrical grid?
From an article in the Financial Times today, about a solar eclipse on March 20th, 2015:
An eclipse of the sun next month could disrupt Europe’s power supplies because so many countries now use solar energy, electricity system operators have…
Nicolas B
- 93
9
votes
1 answer
Why can solar cells be made of indirect and direct semiconductors? (Comparison between some pn-junction devices)
Various textbooks mention, but not go into detail, how semiconductor devices are optimized for their particular function. E-k space is trascendental to understand this, given that it depends on the direct and indirect nature of the semiconductor.…
nomadStack
- 369
8
votes
1 answer
Why is my solar panel more efficient as the temperature increases, rather than less efficient?
I have recently performed an experiment in which I placed a solar panel inside a closed box, together with a heater and a lamp (60W). I increased the temperature using a heater from 20ºC to 50ºC. The lamp remained switched on the whole time.
I´ve…
Pablo Vidal
- 81
- 1
7
votes
2 answers
What is injection level (semiconductor physics)?
I am currently reading journal articles about semiconductor physics in solar cells. What is injection level?
I'll try to start off with what I understand. Photons hitting the silicon cause its electrons to jump to a higher energy state. Some of…
Kit
- 1,483
6
votes
5 answers
Why do solar cells have a window layer on top of the absorber layer and not below it?
In solar cells there is a p-n junction. P-type semiconductor (for example CdTe) is often absorber layer because of its carrier lifetime and mobilities. In case of CdS/CdTe,* CdS is n-type window layer and everywhere it is said that it should be very…
Stanpol
- 193
- 1
- 5
6
votes
3 answers
To grow one $\rm m^2$ of crop plants, how many $\rm m^2$ of solar panels do you need?
In vertical farms you need to use LEDs to make plants grow, which in turn have to be powered e.g. by solar panels. If solar panels had the same efficiency as plants, then you would need the same amount of solar panels as you had plants before, if…
Felix Benning
- 183