Questions tagged [solar-cells]
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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 ...
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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 ...
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Is plant photosynthesis more efficient than solar panels?
Is photosynthesis more efficient than solar panels? If so, by how much?
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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?...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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Materials for use in a solar cell
In a solar cell, photons of the incident sunlight supply energy for excitation of electrons - a process which generates electron-hole pairs which can move under the influence of the electric field of ...
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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 ...
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Do solar panels work when they are at the temperature of the incoming light?
Let us say we have this high-temperaterature solar panel that can tolerate being heated to above the black-body temperature of light frequency it collects.
Does the panel continue to generate power ...
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Why aren't solar panels efficient?
Why can't solar panels produce 1 Kw per 1 square meter? This is the energy of the Sun's radiation per square meter on Earth but solar panels don't come close. Why can't we trap all that energy? ...
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What is the most efficient Organic Photovoltaic solar cell?
Preferably one that is researched in a paper, not necessarily in production.
I have found various claims of OPVs with an efficiency of 10%, 8% and 7.3%, the only one I can substantiate is referenced ...
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If the energy of photons at the bottom of the visible spectrum (~720 nm) is 1.72 eV, why does a red LED light up at only 1.48 V?
I have a red LED (623 nm peak wavelength) which I am able to light up at 1.48 V. I thought the switch-on voltage should be determined by $hc/(e\lambda)$, but that would give 1.99 V for 623 nm. Even ...
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How does temperature affect photovoltaics (PV) efficiency?
I know that photovoltaic panels are more efficient at lower temperatures: As the temperature increases, the output voltage decreases. I am looking for an explanation of the mechanism behind this ...
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Doubt about the working principle of a silicon solar cell
I'm studying crystalline solar cell and their working principle, but I still don't completely understand the process.
First of all, I understand that we dope a pure crystalline silicon with boron and ...
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How much solar energy hits a rooftop in Israel?
I was asked to today about the available plans (in Israel) to install photo-voltaic receptors on the roof and sell the energy. This is a legitimate plan and there are several companies that do this. ...
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In the diode equation, why the exponential $\exp$ and the ideality factor $n$ are there? What do they represent & what is their significance?
In the Shockley diode equation, why the exponential $\exp$ and the ideality factor $n$ are there? What do they represent & what is their significance?
I have to work on Solar Photovoltaics, and ...
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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 ...
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Would putting a magnifying glass on a solar panel be beneficial? [duplicate]
During my childhood, it was common to use magnifying glasses to burn paper and dead leaves.
But would it be a good idea to place a lens above a solar panel, making sure that all the magnified light ...
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Why do silicon solar cells only produce ~0.6V when the band gap of silicon is ~1.1V?
I've been researching into this and can't quite figure out where that lost voltage is going. When silicon is excited by a photon within its absorption spectrum, it will always have an internal ...
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Does the albedo of a photovoltaic cell correlate with its load?
Exactly what the title says. Since solar panels convert (to my understanding) visible light into electricity, will a solar panel under load appear visually darker compared to a solar panel under no ...
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Combining the energy from two optical fibers transmitting visible light
Can this be done?
It wouldn't violate energy conservation...
I've tried looking at 1xN beamsplitters used in reverse. But it won't work, since using them in reverse also splits the incoming power ...
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Photomagnetic effect
I just saw an article on wikipedia: http://en.wikipedia.org/wiki/Photomagnetic_effect
"This article appears to contain unverifiable speculation and unjustified claims. Information must be verifiable ...
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Solar panels that also work at night?
This was first proposed in a scientific study from 2019. Essentially, the idea is that the solar cell generates power from the heat it radiates at night. That study claimed a theoretical maximum ...
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We just need a solar panelled SPAIN to power the world? [closed]
A stiffer, more formal (form, schmform!) way to ask this is:
Is a solar panel field the size of Spain enough to cover the worlds energy needs?
(This assumes that everything in the world runs on ...
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"Single-shot" Heat engine efficiency limits
The sun is 5778K and Earth is ~290K. Using the sun as the hot reservoir and earth as a cold reservoir we get 95% Carnot efficiency. However, the solar power efficiency limit is only 86%, see: http://...
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What is up and down conversion in photonics?
I have heard the terms up and down conversion in photonics/photovoltaics articles. What do the terms mean?
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Why are solar panels blue, rather than black, when black absorbs more light?
This is an image of a solar panel array, courtesy of Wikipedia.
Some of these look rather black, but most of them are blue.
As far as I know, solar panels work by absorbing "light energy", and then ...
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Would it be possible to build a Solar Panel Etalon?
Since, on average, 1/3 of all sunlight that hits a solar panel is reflected, wouldn't it be possible to set up some kind of etalon system where the reflected light is then absorbed by another solar ...
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Why don't solar panels eventually reach electrical charge equilibrium?
Here is my understanding: Solar panels work based on electrons from an N-type semiconductor losing electrons that travel from a metal grid, through whatever you're powering, to the back grid where ...
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Increasing the efficiency of photovoltaic power cells
Given that solar cells use one or more semiconductor materials to convert light to electricity, and that the efficiency of that conversion is dependent on the material and the wavelength of the light, ...
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How far from the Sun is a photovoltaic effective?
Just what the title states.
Photovoltaic cells convert incident light to electricity; this probably means they create less electricity when it is dark - as in deep space.
How far can a solar cell ...
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$V$-$I$ characteristic of a solar cell
please explain the VI characteristics of a solar cell. The characteristics is given in my book without any explanation. How can the Voltage decrease on increasing current shouldn't it be opposite.
...
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Is a photovoltaic powered air conditioner neutral to global warming?
Is my assumption correct, that
Power generated by photovoltaic solar panels reduces heat energy
from the sun (according to the PV cell efficiency of around 20%) on
the area they cover
An A/C ...
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In a photovoltaic effect, when the electron absorbes the photon, is the electron's energy displaced?
I'm a super amateur wannabe physicist, and I'm trying to learn the fundamental workings of the photovoltaic effect.
I haven't been able to understand "how" or "what" is displaced/...
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How do solar panels generate infinite electricity?
We know that solar cells generate electricity utilizing the energy of the photon, but how can they generate electricity forever?
In a n-type terminal we have the bond of silicon and phosphorous so ...
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Why the direct band gap semiconductor get higher optical absorption coefficient than indirect band gap semiconductor
I can understand that direct band gap semiconductor doesn't need phonon to absorb light.
But in the following formula:
The optical absorption coefficient is proportional to the square of $h\nu$ in ...
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Why is $I$-$V$ characteristics of a solar cell drawn in the 4th quadrant?
My book says because a solar cell does not draw current but supplies it to the load. I don't quite get the explanation. How is it related?
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Given mean insolation, can one place an upper bound on the daily peak insolation?
Photovoltaic panels are rated under standard conditions: eg a $100\mathrm{W}$ panel if irradiated with $1000\mathrm{W}/\mathrm{m}^2$ at $25^\circ\mathrm{C}$.
When the cost effectiveness of ...
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Confused about charge seperation in solar cells
I'm a bit confused about how solar cells work.
My understanding is that there is a p-n junction. A photon is absorbed which creates an electron-hole pair, and the idea is to separate the electron ...
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Lab Construction of LED
If given a semiconductor with known bandgap, how might someone construct an experimental LED within a lab? It seems common to prepare solar cells using FTO glass plates with a paste of semiconductor ...
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What does it mean if the resistance of a semiconductor increases due to light?
I have synthesized an $n$-type semiconductor material $\text{ZnO}$. Under light illumination, its resistance keeps increasing. What are the reasons for this?
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Light - Indium Tin Oxide Interaction
I need to understand the mechanisms behind the light - indium thin oxide interaction for an ITO deposited solar cell. Does it act like a metal or semiconductor? Does it generate electron-hole pairs ...
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Do Solar Cells Regenerate After Exposure to Ionising Radiation?
In the past, plenty of research has been done on the effects of ionising radiation on solar cells. This is due to the importance of high efficiency solar cells for electric spacecraft propulsion. Such ...
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By what maximum amount can we concentrate sunlight?
This refers to a previous question re: Solar Cell Systems and as part of the answer the statement:
If we concentrated sunlight to [the] maximum amount 42600× was given.
My questions are:
By what ...
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