Questions tagged [solar-cells]

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Why are polycrystalline solar cells shinier than monocrystalline solar cells?

Being shiny reduces the efficiency of the solar cells. Additional to the grain boundaries that polycrystalline solar cells have that gives resistance to the current flowing in them, they are shinier ...
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4answers
64 views

Is silicon a semiconductor or insulator?

I have read that pure crystalline silicon is an insulator because it has a such covalent bond that very tight and no free electrons available for conduction bands. They all are bonded with other ...
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Does open-circuit voltage decrease when resistance increases in a solar cell?

In a solar cell, if resistance were to somehow increase (maybe heating up the panel), would that contribute in any meaningful way in decreasing the open-circuit voltage?
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Why are monocrystalline solar cells more efficient than polycrystalline solar cells?

What causes monocrystalline silicon to be more efficient than polycrystalline silicon in the production of a solar cell? I have read this answer on Reddit: In general, single crystal is always better ...
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2answers
82 views

Why do solar cells need to be square-shaped? [closed]

There were circular solar cells 30 years ago. Why do we have square-shaped solar cells now? Why square? Furthermore, Why do monocrystalline solar cells have rounded/cropped edges? Taken from: https://...
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36 views

How do solar panels lose efficiency and die over time?

Why do solar panels have a limited amount of lifespan? What goes wrong in them by the time passes? What changes happen in them that causes it to lose efficiency? What are the factors? It seems to me ...
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1answer
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In a solar farm why isn't there a single gigantic solar panel across all the farm surface, rather than small individual separate panels? [closed]

Why don't we just cover all the farm surface with one solar panel? Why is there a necessity for making separate but multiple panels rather than one large panel that covers the whole necessary space?
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36 views

What is the physical explanation behind the decrease of open circuit voltage as temperature increases in an amorphous solar PV cell?

I have researched and looked at several papers describing the effect of temperature on the $I_{sc}$ and $V_{OC}$, and seen many numerical explanations as to why the voltage drops, with reference to I-...
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3answers
45 views

Why does solar panel output vary across the day?

I have seen engineering projects where they build a solar panel to track the sun such as this one However, I don't understand their rationale fully. They argue that at one point in the day, the sun is ...
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2answers
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How do photovoltaic panels obey the law of conservation of energy?

The sun shines on a photovoltaic panel and it makes electrical energy, presumably by absorbing the photons in the incident light. But where does the energy transferred into electricity come from? Does ...
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45 views

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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27 views

Solar panel voltage reducing by adding cellophane

For a physics report, I am aiming to answer the question How does the power output of a solar cell vary with the thickness of cling wrap laid over it? I got a negative relationship between voltage and ...
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38 views

Can waste heat in specific environments be collected into photons and converted to electricity? [closed]

Crossposted on Engineering SE Here and here show possibility to combine photons of lower energy to one higher. Thinking of an application, it could be used to dissipate heat from laptop. Liquid ...
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1answer
45 views

In a solar cell when an electron is freed due to light in the depletion layer, why does it move to N-type layer even though it is negatively charged?

Even though in a solar cell the N-type layer is negatively charged why do the electrons from the depletion layer get attracted to it?
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21 views

Why do Photo diodes in Computer Mouses don't generate electricity when receiving light? [closed]

I had been researching about photovoltaic cells recently for a science project. In my researches,I stumbled upon photovoltaic cells,silicons,solar cells,and photodiodes. Photodiodes and Solar panels ...
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30 views

Work done by a Photovoltaic cell

Is the electrical work done a Photovoltaic cell equal to the energy of the photon incident upon the cell? (Assuming energy is not lost/gained due to other interactions) If we do not discard other ...
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1answer
38 views

Physics behind Long-distance Wireless Power

I have been looking into Solar Based Solar Power (SBSP) satellites to utilize the radiated energy of the Sun and utilize for use back here at Earth. The idea is that these satellites contain solar ...
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1answer
35 views

Photon replaced by gas atoms in solar panels systems [closed]

Could be replaced photon in solar energy systems by the pressured non-ideal gas? Have gas atoms enough energy to hit electrons out in the material in solar panel?
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2answers
106 views

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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How are the layers of a solar cell stacked together?

Do manufacturers of solar cell use an adhesive to bind the n-type and p-type layers of a solar cell?? Or do they simply rely on the smoothness of the surfaces of the individual layers to contact each ...
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1answer
29 views

Why is exciton diffusion a problem in organic photovoltaics and not in inorganic photovoltaics?

On page 2 of this paper: "When the incident photon hits electrons at the ground state, inorganic semiconductors generate free carriers. However, in organic semiconductors, excited electrons ...
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18 views

The mechanism behind the second order non-linear injection current

In this paper the mechanism of second order non-linear injection current is defined as Injection currents are produced by quantum interference between different polarization components or between one ...
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1answer
50 views

Why clear days are not alike: What's the atmospherical science of a clear day? [closed]

I was hoping for an ideal clear day (synoptically clear sky) to see the maximum power output for my solar setup at my latitude (43.5804° N, 7.1251° E). Simple enough I thought weeks ago. Well over the ...
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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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29 views

Why shift current doesnt depend on applied voltage?

I am currently reading about the Bulk photovoltaic effect in Weyl semi-metal. Shift current is one of the major sources of current in the Bulk Photovoltaic effect. They originate in non-...
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1answer
86 views

Why does solar cell performance use short-circuit current per unit area and open-circuit voltage without reference to the cell area? [closed]

Here on this slide on page 54: Only the short-circuit current ($J_{SC}$) is given with respect to area, whereas the voltage stands without relation to area. One could calculate it, because the area ...
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1answer
115 views

What is the relation between the short-circuit current and the band gap energy in solar cells?

For the VOC it is: VOC = E_g - something, where something is positive and depends on the Urbach energy. Otherwise it should be linear: https://aip.scitation.org/doi/pdf/10.1063/1.49397 For the ISC I ...
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1answer
53 views

How many hot electrons are in solar cells that do not thermalize?

When an electron in a solar cell is excited beyond the conduction band edge, it will most likely thermalize which can only be counted as a heat loss. But in a few cases the electron will directly ...
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1answer
54 views

Why don’t illuminated series connected (photo-)diodes bias each other?

When you connect, let's say, three photodiodes or solar cells, with a load, and you measure the voltage across the middle photodiode. Will the voltage change if the adjacent cells are in the dark if ...
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1answer
27 views

Why can it be important to engineer band alignments/offsets (e.g. CdS buffer layer in CIGS)?

I would like to ask this question by the example of the CdS buffer layer in CIGS solar cells. One paper (https://pubs.rsc.org/en/content/articlelanding/2017/se/c7se00348j#!divAbstract) says that CdS ...
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1answer
127 views

Why is the diffusion length defined for minority charge carriers only?

As far as I could infer from the solar cell literature, when talk is about the "diffusion length", only the minority carriers are concerned. Is there a diffusion length defined for majority ...
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1answer
87 views

Why are we even interested in solar cells under bias voltage?

I couldn't find any answer on this super basic question. Some people on the internet say that you would not put a solar cell in an array under bias, others say that they bias themselves, but I don't ...
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1answer
35 views

How should one systematically optimize various solar cell device parameters to achieve highest possible efficiency in a solar cell simulation? [closed]

I am confused as to which parameter I should start off with in order to optimizing the best performing solar cell. There are parameters like Thickness, Bandgap, Electron Affinity, relative Dielectric ...
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1answer
59 views

What are the different driving forces behind a solar cell and how is a voltage created?

I have a hard time understanding the I-V curve of a solar cell. I dont understand how in an short circuit a current can happen although there is no voltage? Isn't voltage the requirement for a current,...
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Why do we need pure silicon for a solar cell to be efficient?

Why is it that we need ~99% pure silicon in order to have efficient solar cells? I understand that as silicon purity decreases so does solar cell efficiency but I'd like to understand why.
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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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1answer
21 views

Position dependent $y$ channel reading in lock-in in a photocurrent microscope setup

I am currently building a scanning photocurrent measurement setup. It basically focuses a CW laser down to $50\ um$ size on the sample and scan the laser beam over the sample (a metal) and record the ...
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1answer
66 views

Can UV lamp's light charge solar cells?

If you try to make some solar thing work from a UV lamp, but it doesn't, does it mean that it's not a real UV? The lamp I tried smells like ozone when works, it emits light blue color when works.
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2answers
177 views

How current is produced in photoelectric cell?

In photoelectric cells, a current is detected when photoelectrons reach the electrode on the opposite side of the tube after being emitted. But shouldn't current be detected when photoelectrons leave ...
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1answer
90 views

Intrinsic carrier concentration and bandgap

My understanding is that the intrinsic carrier concentration of a wide bandgap material tends to be lower than that of a narrow bandgap material. $$ n_i = \left(N_cN_v\right)^{1/2}e^{\left(\frac{-E_g}...
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2answers
57 views

Does solar cells absorb sub-bandgap photons?

My understanding is that although we are taught that solar cells only absorb photons of energy higher than the bandgap of the material, some of the sub-bandgap photons still gets absorbed, which is ...
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Dependence of solar energy absorbed over a year on orientation of solar panel

I am trying to find how total solar energy incident, over a year, depends on the orientation of a tilted solar panel. The final goal is to find the optimum direction in which the panel should be ...
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pn junction: band bending vs. fermi level bending [closed]

① I have two semiconductors of the exact same material. Hence, the conduction band and the valence band are exactly on the same level. The same holds for the vacuum level. Now the left one is p-doped, ...
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How does perovskite solar cell work?

Do you dope the perovskite material the same way you dope silicon? Is there a P-type perovskite and N-type perovskite inside the cell?
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Does incoming light polarization and phase effect the efficiency of photovoltaic cells?

As I understand it, standard photovoltaic cells depend on both the creation of electron-hole pairs and those pairs being created in the depletion zone in a P-N junction. Is seems like the production ...
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3answers
724 views

$V$-$I$ 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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34 views

How much solar power in kWH is there in the stratosphere during the day? [closed]

The stratosphere is above much of the atmosphere. People have talked about collecting solar energy there and beaming it back to Earth. How much power are we talking about?
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Incident Photon to Converted Electron vs. UV-VIS absorbance

We can define the Incident Photon to Converted Electron (IPCE) for a solar cell as the ratio of photons that strike the solar cell to the number of electrons that flow out of the cell. Hence, we can ...
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39 views

Thermodynamic limits to photovoltaic or photochemical processes

Photovoltaic or photochemical (photosynthesis) processes are basically extracting energy from the temperature difference between the Sun and Earth. In practice they are only able to capture photons in ...
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2answers
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Would this work as a way to get more energy from sunlight? [closed]

Plants only absorb certain wavelengths of light. This leaves a lot of light useless. But... imagine putting plants on a wheel and spin that wheel very fast. Then the light is red-shifted and so the ...

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