In solar cells, is the photosensitive layer p type?

Are you talking about PN Junction solar cells?

P type doping semiconductors are hole with a relatively high concentration.

n type doping semiconductors are electron (electron) concentrations are relatively high.

So in the p-layer, the Fermi level is closer to the valence band, and in the n-layer, the Fermi level is closer to the conduction band, and when the p-n semiconductors are connected together, their Fermi levels will be at the same energy level.

And the generation and migration of electrons is the generation of electron pairs (electron & hole) from the p-layer, the electrons jump to the valence band and then migrate to the valence band of n-type semiconductors, because the electrons prefer to stay in a place with lower energy.

So the photosensitive layer is the p-layer.

To be exact, the landlord's question is a bit general:

Not only is the transition zone between n-type or p-type or the two types photosensitive, but the solar energy will have a photoelectric effect when it hits the material.

Because the type of carriers generated by the photoelectric effect of solar cells is electrons, the electrons in the p-type region (the main carrier is vacant) are immediately recombined and no current is generated; Whereas, in the n-type region (where the main carriers are electrons), electrons can accumulate. Ultimately, the photoelectrons generated at the N-P type reversal will move in a directional manner due to the presence of a built-in electric field, and when there is an external wire, an electric current will be generated.

Hope solves the landlord's doubts. Thank you!

The basis is the Pn junction, and the photosensitive layer can make the P layer or the N layer, but different photosensitive layers have different utilization rates for light.

In addition, the absorption intensity of sunlight by solar cells is exponentially attenuated, that is, the closer to the photofacing surface, the more sunlight is absorbed, so a large number of photogenerated carriers are generated on the photopositive side. With the p-layer as the photofacing surface, the path of hole transport to the p-layer is short, which is conducive to collection, and although the electron transport distance is long, the loss is small due to its large mobility.

If it is a crystalline silicon cell, the substrate is P-type wafer, then brush a layer of Al as described upstairs to make the back electrode, and then carry out high temperature treatment in a sintering furnace of about 500-600 degrees, at this time, Al and Si reach the eutectic point to form Al-Si alloy, and part of Al enters Si to form the so-called low and high junction! That is, BSF is formed!!

If it is a HIT structure, it is necessary to dope the layer with the same conductive type as the substrate but with a high doping concentration by doping and deposition by chemical vapor phase means such as PECVD, and the Pp+ or NN+ structure is formed from the physical image.

Crystalline silicon cells are printed with a layer of 3valent Al backfield by screen printing, and then sintered at high temperature in a sintering furnace. OK, the P+ layer is formed!

The main material of solar cells is polysilicon, which can only be said to be relatively environmentally friendly, and will not produce waste in the process of use, and reproduction will consume energy to produce waste.

Polymer silicon solar energy is energy-saving and environmentally friendly when used, but it is polluting to a certain extent during production.

The production process is polluting, and people are now expecting too much from the solar industry, and many companies are now in a recession.

I'll answer your question about the components you need. The current market price is 12 yuan a w, that is, the money you need to invest in the module is 120w yuan, plus the inverter controller battery wire installation labor according to the market ** you install is estimated to require 50w yuan, the country's subsidy for the installation of solar energy seems to add up to half of your installation, that is to say, you have to take out more than 80w, the size of the system you install is very chicken, if the power station is too small, if you say that the household use, 1-5kw is enough.

You can only tell you roughly that the solar power generation system installed by the country is about 30-35 yuan, and if you install it yourself, it can be lower, after all, the country's water content is still some.

How much area do you want. And there is a problem with your topic.

The emission region is the region where the carriers are injected, generally the high doping region, in addition to the intrinsic region and the collection area, the eigenlayer is the area without doping, you can take a look at the semiconductor device book written by Shi Min, which is more basic.

Under the action of the built-in electric field of the p n junction, the photogenerated holes flow to the p region, and the photogenerated electrons flow to the n region, and the current is generated after the circuit is turned on. This is how photoelectric effect solar cells work.

The light-heat-electricity conversion method uses the heat energy generated by solar radiation to generate electricity, which is generally converted by a solar collector into the vapor of the working fluid, and then drives a steam turbine to generate electricity. The former process is the light-heat conversion process; The latter process is a heat-to-electricity conversion process, as is the case with ordinary thermal power generation.

The principle of photovoltaic cell power generation can be said to be the principle of photovoltaic power generation

Photovoltaic power generation is a technology that directly converts light energy into electrical energy by using the photogenerated volt effect at the semiconductor interface. The key element of this technology is the solar cell. Solar cells can be encapsulated and protected in series to form large-area solar cell modules, and then combined with power controllers and other components to form photovoltaic power generation devices.

The main specific principle of photovoltaic power generation is the photoelectric effect of semiconductors. When a photon irradiates a metal, its energy can be absorbed by an electron in the metal, and the energy absorbed by the electron is large enough to overcome the internal gravity of the metal to do work, escape from the metal surface, and become photoelectrons. A silicon atom has 4 outer electrons, and if an atom with 5 outer electrons such as a phosphorus atom is doped into pure silicon, it becomes an n-type semiconductor; If an atom with three outer electrons such as boron atoms is doped into pure silicon, a p-type semiconductor is formed.

When p-type and n-type are combined, a potential difference is formed at the contact surface, which becomes a solar cell. When sunlight hits the p n junction, the holes move from the p pole region to the n pole region, and the electrons move from the n pole region to the p pole region, forming an electric current.

The photoelectric effect described above is a phenomenon in which light causes a potential difference between an inhomogeneous semiconductor or between a semiconductor and a metal. It is first of all the process of converting photons (light waves) into electrons and light energy into electrical energy; Secondly, there is the process of forming a voltage.

Principle of solar battery power generation: A solar cell is a device that responds to light and converts light energy into electricity. There are many kinds of materials that can produce photovoltaic effects, such as:

Monocrystalline silicon, polycrystalline silicon, amorphous silicon, gallium arsenide, selenium, indium copper, etc. Their power generation principle is basically the same, and crystalline silicon has been used as an example to describe the process of light power generation. P-type crystalline silicon can be doped with phosphorus to obtain n-type silicon, forming a p-n junction.

When light hits the surface of a solar cell, a portion of the photons are absorbed by the silicon material. The energy of the photons is transferred to the silicon atoms, so that the electrons undergo a migration, becoming free electrons and accumulating on both sides of the p-n junction to form a potential difference, when the external circuit is turned on, under the action of this voltage, there will be a current flowing through the external circuit to produce a certain output power. The essence of this process is the process of converting photon energy into electrical energy.

What are Semiconductors? What is the difference between n-type and p-type? Principle of solar cells (above).

Hello, let me come to your question, that's what I'm doing. There are many factors that affect the conversion efficiency of solar cells, so let's summarize them simply: 1) Solar light intensity.

A solar cell is a device that converts sunlight into electricity, and in general (pay attention to the conditions), the efficiency of the solar cell increases with the increase of light intensity. Furthermore, the efficiency of solar cells is related to the comprehensive climatic conditions of the place where they are installed. 2) The material of the battery.

Different materials have different absorption coefficients for light, different band gaps, different quantum efficiency, and different cell efficiency. Generally speaking, the coefficient coefficient of monocrystalline silicon and polycrystalline silicon to light is much smaller than that of amorphous silicon, so the thickness of amorphous silicon solar cells is only one percent of the thickness of monocrystalline silicon and polycrystalline silicon to absorb sunlight better. In addition, theoretically, the ultimate efficiency of Gaas solar cells is greater than that of other solar cells, because the bandgap width of Gaas solar cells is the closest to the maximum value of ground solar spectral energy.

3) Process level. Different process levels, the efficiency of the battery is naturally different, look at each factory to understand why the raw materials are almost the same, but the efficiency of the cells made is very different, the reason is this. Generally speaking, the more advanced the equipment, the better the process, the higher the battery efficiency (the process is the product of the equipment, and the process cannot be realized without the equipment, it is all utopian).

Typical examples are sin:h anti-reflection coating and inverted pyramid structure, and if a battery does not use these two processes, the efficiency will vary greatly (about 8%). Typical processes in actual production are:

Suntech's "Pluto", JA Solar's "Maple", Yingli's "Panda" and so on.

New energy is a new economy, and the development of the new economy in the early stage is an exponential explosive growth, and the prospects of this industry are good. But Chinese are easy to be hot-headed, swarming, and now there is a saying that "buy a slicer and say that you are a certain photovoltaic company", so that the development of the battery industry will repeat China's color TV industry, suffer themselves, and enrich others. The battery industry is now on fire and there is no reason, state-owned enterprises have also come in to mix, a pot of porridge is stewed in this mess, I believe that the industry will be reshuffled in the next few years, who is a mule and who is a horse is naturally clear at a glance.

In addition, the development direction of the photovoltaic industry (in recent years) is vertical integration, but whether this model can be transformed into a classic remains to be examined. There are polysilicon ** manufacturers have entered the middle and lower reaches, and battery manufacturers have also entered the upstream polysilicon, and now it is such a scene, those who make batteries are more concerned about how to make silicon materials, and those who do silicon materials are more concerned about how to make batteries, but no one cares about the most core equipment of batteries, and researchers in universities are, and the state has invested a lot of money, so they have changed them to invoices, but they don't see the equipment come out.

To borrow a phrase to summarize "the road is bumpy, the future is bright"!

According to the formula EFF=PM (MS), the conversion efficiency is related to the light intensity and cell area.

The fill factor ff=pm (uoc*isc), so eff=ff*uoc*isc (ms).

Therefore, the loss of short-circuit current, open-circuit voltage, and fill factor will have a certain impact on the efficiency of the battery.

A completed cell is related to the intensity and area of sunlight.

Plus one, also related to temperature, in general, the conversion efficiency decreases with the increase of temperature.

1 Material and light-receiving area.

2 The range of sunlight's light waves.

3 The intensity of sunlight.

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