Questions tagged [solar-cells]

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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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0answers
22 views

Carrier concentration - distance graph of PN junction [closed]

i am trying to plot the distance-carrier_concentration graph above with these "wide base" formulas: and (p-side: x < -xp , n-side: x > xn) But i could draw only red lines on the ...
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1answer
47 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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0answers
18 views

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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0answers
25 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
43 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
26 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
49 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 ...
2
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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
24 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
43 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
69 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
30 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 ...
1
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1answer
42 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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2answers
36 views

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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0answers
86 views

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 ...
1
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1answer
19 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 ...
2
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1answer
62 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
69 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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0answers
24 views

Photovoltaic cell - why the side with silver produces less current that the side with gold?

In a recent experiment done during my second year of physics bachelor's degree, I built a photovoltaic cell by evaporating silver on one side of a thin silicium tablet and then gold on this other side....
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0answers
12 views

Can you apply horizontal shift to obtain the absorption spectra for III-V ternary and quaternary compounds

For a multi-junction (MJ) solar cell application, can you apply a horizontal shift to obtain the absorption spectra when you don't have the available data? For example, if you know the absorption ...
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1answer
63 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
32 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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0answers
35 views

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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0answers
238 views

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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0answers
24 views

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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21 views

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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0answers
14 views

I have a percent loss of the power output of a PV cell that isnt 1 meter squared. How can I aplpy the power loss to other panels

I made an experiment were I added sand ontop of a PV panel and measured the decrease in power output. I graphed the percent loss of the power output from when there was no sand. My panel isnt 1 meter ...
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3answers
186 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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1answer
33 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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49 views

Why do we get lower voltage with smaller band gap and higher voltage with larger band gap in a solar cell?

It makes sense to me that if the band gap is smaller, we would get a higher current as more electrons will be promoted to the conduction band. However, I do not understand why voltage is lower. I ...
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36 views

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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1answer
36 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
63 views

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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1answer
36 views

Solar cell short circuit current

In order to obtain a solution to the short circuit current in a solar cell a boundary condition n=p=0 at the junction is imposed. Why only for short circuit current?
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1answer
45 views

Calculating output of a solar cell

If we are given a particular solar panel with some semiconductor tabs in it, How can I calculate the output of the Solar panel per metre square With the values of ( average hours of sun everyday, ...
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0answers
24 views

Solar cell: Surprising change in EL for varying PEDOT:PSS-thicknesses

I am currently working on improving a solar cell, which is partly transparent and therefore utilizes two transparent electrodes (TCO on top and PEDOT:PSS on the bottom). As PEDOT:PSS alone is not ...
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1answer
232 views

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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0answers
30 views

Open circuit voltage of solar panel in relation to temperature

How do we calculate the effect of temperature on the open circuit voltage of a solar panel? The source: https://www.pveducation.org/pvcdrom/solar-cell-operation/effect-of-temperature offers an answer,...
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1answer
78 views

How can one determine the key characteristics of a solar cell from the I-V curve?

I have recently measured the IV characteristics of several Si solar cell samples and am now attempting to extract the series resistance $R_S$; parallel resistance $R_P$; open circuit voltage $V_{OC}$; ...
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4answers
9k views

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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1answer
37 views

Does quantum efficiency of solar cells vary with irradiance?

I want to know if a solar cell exposed to high irradiance (perhaps artificial light) of say 1500 w/m2 would suffer reduced QE. For the sake of the question lets assume the solar cell is in an ...
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1answer
66 views

what limitations stop a person from installing solar panels on his/her house? [closed]

Solar energy is a great form of energy. sourced from the sun, it can save a great deal of electricity bill cost. My question is why doesn't everyone uses it and install panels on their roof. Of ...
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0answers
163 views

Light Intensity vs Power for a Small Incandescent Lamp

Today I did a quick experiment where I measured the light intensity of a small incandescent bulb for a range of voltages (0 to 31V). I also measured the current. I expected to see the light ...
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1answer
85 views

Does doped semiconductor have free electrons at 0K?

For intrinsic semiconductors, they don't have any free electrons at conduction band at 0k and behave like insulators. But if doped, let's say n-type doped, they will have extra electrons which do not ...
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0answers
91 views

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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2answers
69 views

Will the electron-hole pairs in a solar cell ever run out?

I have read from various sources that, the photon strikes the solar cell and creates and electron hole pair which then migrates to their respective ends of the cells, this creates a potential ...
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1answer
76 views

Where do photons excite electrons in the PN junction?

Assuming a Si-Boron P-type, and Si-Phosphorous N-type solar cell. N-type is on top and P-type is bottom. I understand that after both semiconductors are layered a depletion zone is formed. Where e- ...
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1answer
51 views

Depletion layer of solar cell? [closed]

What happens to depletion layer of solar cells when light is falling on it? Please reply as soon as possible. Thank you