Different types of solar cells

– Introduction:

Any device that straight converts the energy in light into electrical energy through the photovoltaic consequence, are called solar cells. Unlike batteries or fuel cells, solar cells do non use chemical reactions or necessitate fuel to bring forth electric power, and, unlike electric generators, they do non hold any moving parts. Solar cells can be arranged into big groupings called arrays. These arrays, composed of many 1000s of single cells, can work as cardinal electric power Stationss, change overing sunshine into electrical energy for distribution to industrial, commercial, and residential users. Solar cells in much smaller constellations, normally referred to as solar cell panels or merely solar panels, have been installed by householders on their rooftops to replace or augment their conventional electric supply. Solar cell panels besides are used to supply electric power in many remote tellurian locations where conventional electric power beginnings are either unavailable or prohibitively expensive to put in. Because they have no moving parts that could necessitate care or fuels that would necessitate refilling, solar cells provide power for most infinite installings, from communications and conditions orbiters to infinite Stationss. Another turning application of solar cells is in consumer merchandises, such as electronic playthings, hand-held reckoners, and portable wirelesss. Solar cells used in devices of this sort may use unreal visible radiation every bit good as sunshine. hypertext transfer protocol: //www.answers.com/topic/solar-cell

– Different types of solar cell:

There are three chief types of solar cells, which are distinguished by the type of crystal used in them. They are monocrystalline, polycrystalline, and formless. To bring forth a monocrystalline Si cell, perfectly pure semiconducting stuff is necessary. Monocrystalline rods are extracted from melted Si and so sawed into thin home bases. This production procedure guarantees a comparatively high degree of efficiency.

-Monocrystalline Si: Efficiency in Lab about 24 % and Efficiency of production cells 14-17 % .
-Polycrystalline Si: Efficiency in lab about 18 % and efficiency of production cell 13-15 % .
-Amophas Si: Efficiency in lab about 13 % and efficiency of production cell 5-7 % .

The production of polycrystalline cells is more cost-effective. In this procedure, liquid Si is poured into blocks that are later sawed into home bases. During hardening of the stuff, crystal constructions of changing sizes are formed, at whose boundary lines defects emerge. As a consequence of this crystal defect, the solar cell is less efficient. hypertext transfer protocol: //www.daviddarling.info/encyclopedia/S/AE_solar_cell.html
If a Si movie is deposited on glass or another substrate stuff, the consequence is a alleged formless or thin-layer cell. The bed thickness sums to less than 1µm – the thickness of a human hair for comparing is 50-100 µm. The production costs of this type are lower because of the lower stuff costs. However, the efficiency of formless cells is much lower than that of the other two cell types. As a consequence, they are used chiefly in low power equipment, such as tickers and pocket reckoners, or as facade elements.
hypertext transfer protocol: //www.daviddarling.info/encyclopedia/S/AE_solar_cell.html

– METHDOLOGY: ( A ) .Solar cell construction and operation:

Solar cells, whether used in a cardinal power station or a reckoner, have the same basic construction. Light enters the device through an optical coating, or antireflection bed, that minimizes the loss of light by contemplation ; it efficaciously traps the light falling on the solar cell by advancing its transmittal to the energy-conversion beds below. The antireflection bed is typically an oxide of Si, Ta, or Ti that is formed on the cell surface by spin-coating or a vacuum deposition technique. hypertext transfer protocol: //www.answers.com/topic/solar-cell

The three energy-conversion beds below the antireflection bed are the top junction bed, the absorber bed, which constitutes the nucleus of the device, and the back junction bed. Two extra electrical contact beds are needed to transport the electric current out to an external burden and back into the cell, therefore finishing an electric circuit. The electrical contact bed on the face of the cell where visible radiation enters is by and large present in some grid form and is composed of a good music director such as a metal. Since metal blocks visible radiation, the grid lines are as thin and widely spaced as is possible without impairing aggregation of the current produced by the cell. The back electrical contact bed has no such diametrically opposed limitations. It need merely work as an electrical contact and therefore covers the full back surface of the cell construction. hypertext transfer protocol: //www.answers.com/topic/solar-cell

Since most of the energy in sunshine and unreal visible radiation is in the seeable scope of electromagnetic radiation, a solar cell absorber should be efficient in absorbing radiation at those wavelengths. Materials that strongly absorb seeable radiation belong to a category of substances known as semiconducting materials. Semiconductors in thicknesses of about one percent of a centimeter or less can absorb all incident seeable visible radiation ; since the junction-forming and contact beds are much dilutant, the thickness of a solar cell is basically that of the absorber. hypertext transfer protocol: //www.answers.com/topic/solar-cell

When visible radiation falls on a solar cell, negatrons in the absorber bed are excited from a lower-energy “ground province, ” in which they are bound to specific atoms in the solid, to a higher “excited province, ” in which they can travel through the solid. In the absence of the junction-forming beds, these “free” negatrons are in random gesture, and so there can be no oriented direct current. The add-on of junction-forming beds, nevertheless, induces a constitutional electric field that produces the photovoltaic consequence. In efect, the electric field gives a corporate gesture to the negatrons that flow past the electrical contact beds into an external circuit where they can make utile work. hypertext transfer protocol: //www.answers.com/topic/solar-cell

The stuffs used for the two junction-forming beds must be dissimilar to the absorber in order to bring forth the constitutional electric field and to transport the electric current. Hence, these may be different semiconducting materials ( or the same semiconducting material with different types of conductivity ) , or they may be a metal and a semiconducting material. The stuffs used to build the assorted beds of solar cells are basically the same as those used to bring forth the rectifying tubes and transistors of solid-state electronics and microelectronics. Solar cells and microelectronic devices portion the same basic engineering. In solar cell fiction, nevertheless, one seeks to build a large-area device because the power produced is relative to the lighted country. In microelectronics the end is, of class, to build electronic constituents of of all time smaller dimensions in order to increase their denseness and runing velocity within semiconducting material french friess, or integrated circuits. hypertext transfer protocol: //www.answers.com/topic/solar-cell

The photovoltaic procedure bears certain similarities to photosynthesis, the procedure by which the energy in visible radiation is converted into chemical energy in workss. Since solar cells evidently can non bring forth electric power in the dark, portion of the energy they develop under visible radiation is stored, in many applications, for usage when visible radiation is non available. One common means of hive awaying this electrical energy is by bear downing electrochemical storage batteries. This sequence of change overing the energy in light into the energy of aroused negatrons and so into stored chemical energy is strikingly similar to the procedure of photosynthesis. hypertext transfer protocol: //www.answers.com/topic/solar-cell

( B ) . Solar panel design: Most solar cells are a few square centimeters in country and protected from the environment by a thin coating of glass or crystalline plastic.Because a typical 10 centimeter ? 10 centimeter ( 4 inch ? 4 inch ) solar cell generates merely approximately two Wattss of electrical power ( 15 to 20 per centum of the energy of light incident on their surface ) , cells are normally combined in series to hike the electromotive force or in parallel to increase the current. A solar, or photovoltaic ( PV ) , module by and large consists of 36 interrelated cells laminated to glaze within an aluminium frame. In bend, one or more of these faculties may be wired and framed together to organize a solar panel. Solar panels are somewhat less efficient at energy transition per surface country than single cells, because of inevitable inactive countries in the assembly and cell-to-cell fluctuations in public presentation. The dorsum of each solar panel is equipped with standardised sockets so that its end product can be combined with other solar panels to organize a solar array. A complete photovoltaic system may dwell of many solar panels, a power system for suiting different electrical tonss, an external circuit, and storage batteries. Photovoltaic systems are loosely distinctive as either stand-alone or grid-connected systems. hypertext transfer protocol: //www.answers.com/topic/solar-cell

Stand-alone systems contain a solar array and a bank of batteries straight wired to an application or burden circuit. A battery system is indispensable to counterbalance for the absence of any electrical end product from the cells at dark or in cloud-covered conditions ; this adds well to the overall cost. Each battery shops direct current ( DC ) electricity at a fixed electromotive force determined by the panel specifications, although burden demands may differ. DC-to-DC convertors are used to supply the electromotive force degrees demanded by DC tonss, and DC-to-AC inverters supply power to jumping current ( AC ) loads. Stand-alone systems are ideally suited for distant installings where associating to a cardinal power station is prohibitively expensive. Examples include pumping H2O for feedstock and supplying electric power to beacons, telecommunications repeater Stationss, and mountain Lodges. hypertext transfer protocol: //www.answers.com/topic/solar-cell

– Summary:

( A ) .New development on solar cells: The development of solar cell engineering stems from the work of the Gallic physicist Antoine-Cesar Becquerel in 1839. Becquerel discovered the photovoltaic consequence while experimenting with a solid electrode in an electrolyte solution ; he observed that electromotive force developed when visible radiation fell upon the electrode.http: //www.britannica.com/EBchecked/topic/552875/solar-cell/45872/Development-of-solar-cells

( a ) Printable solar cells on the manner:

Research workers from the Victorian Organic Solar Cell Consortium, which includes scientists from authorities research bureau the CSIRO, the University of Melbourne and Monash University, have developed a new technique that could open up the door for inexpensive, mass-produced solar cells. “ These solar cells are cutting border engineering and offer advantages over traditional solar engineering, ” Peter Batchelor, Victorian Minister for Energy and Resources, said at the launch. “ The production of these film-like solar cells will be literally every bit easy as publishing money. “ http: //www.britannica.com/EBchecked/topic/552875/solar-cell/45872/Development-of-solar-cells

( B ) Flexible plastic:

The new cells are printed onto a thin flexible plastic, which ( unlike bing Si solar cells ) can be easy crafted to suit any rooftop. Gerry Wilson, a member of the CSIRO squad, said world has been publishing for centuries and this is one of many possible applications for “ printable electronics. “ The active ingredients in the new solar cells are thin-printed beds of photosensitive inks that absorb energy from the Sun. The research workers said that during an on-going test period these inks would be tested for maximal efficiency.

hypertext transfer protocol: //www.sciencedaily.com/releases/2007/07/070719011151.htm.

Presently, the printable solar cells are two to five per cent efficient, the experts said, something they are seeking to better it “ by tweaking the chemical construction ” of the inks. Solar cells presently on the market scope from 5 to 24 per cent efficiency. hypertext transfer protocol: //www.britannica.com/EBchecked/topic/552875/solar-cell/45872/Development-of-solar-cells

( degree Celsius ) Forefront of polymer engineering:

Jai Singh, a physicist from Charles Darwin University, in the Northern Territory, said that while the engineering is still in its babyhood, it could supply an economical alternate energy beginning. “ They are cost-efficient because the expensive In Sn oxide used in traditional solar cells will be replaced by low cost functionalised graphene beds, ” he said.Australian scientific discipline curate, Senator Kim Carr, said the test was an exciting development for the industry. “ This research is at the head of polymer engineering, which has already brought to the universe the bills used in Australia and 21 other states. It is an of import measure in constructing up the solar industry, ” he said.Andrew Blakers, Director of ARC Centre for Solar Energy Systems at Australian National University said any investing in the industry is ever welcomed and will promote advancement in renewable energy beginnings. “ Australian solar industry needs to be encouraged and good funded in order for Australia to take its topographic point as a universe leader in this industry, ” he said.

hypertext transfer protocol: //www.sciencedaily.com/releases/2008/11/081104114427.htm.

( vitamin D ) Hybrid Materials For Future Solar Cells Under Development:

Semiconductor nanocrystals or besides called quantum points exhibit outstanding optical belongingss compared to organic dyes. Due to the quantum confinement their emanation colour can be continuously tuned from the UV to the close infrared scope by altering the size and chemical composing. They exhibit a wide soaking up spectrum, a narrow emanation set and big soaking up cross subdivisions. Their surface can be covered by a few monolayers of different semiconducting material stuffs in such a manner that we can either better their luminescent belongingss and stableness or avoid the fluorescence to obtain charge bearers. The latter consequence opens enormous options in photovoltaics. Due to their optical belongingss, semiconducting material nanoparticles are studied in different subjects, from optics to biomedicine.

hypertext transfer protocol: //www.sciencedaily.com/releases/2008/11/081104114427.htm.

Scientists can now bring forth nanoparticles of different stuffs commanding their size, form, and surface belongingss. Examples of nanoparticles produced by non hydrolytic colloidal man-made methods are CdS, CdTe, InP, GaAs, PbS, or PbSe. However, the most studied system is CdSe, with tunable emanation from bluish to ruddy. Due to the man-made attack ( hot injection method ) , the surface of these nanoparticles is capped with an organic shell that protects them and makes them stable in non-polar organic dissolvers. It is besides possible to controllably replace the initial organic shell for H2O compatible 1s. The organic shell plays a relevant function in the quantum efficiency of the nanoparticles and their stableness in different media. However, this shell prevents high electrical conductivity. hypertext transfer protocol: //www.sciencedaily.com/releases/2008/11/081104114427.htm.

Carbon nanotubes are another illustration of nanomaterials with extraordinary electrical belongingss. They consist of one or several rolled up graphene beds. In the instance of a individual bed they are called single-wall and multi-wall when several beds are rolled-up. Hybrid stuffs composed of semiconducting material nanoparticles and C nanotubes combine the high soaking up belongingss of the former and the high electrical conduction of the latter. hypertext transfer protocol: //www.sciencedaily.com/releases/2008/11/081104114427.htm.

One of the chief drawbacks in the formation of such intercrossed constructions focuses on the type of interaction between them. Most of the bing processs involve the growing of nanoparticles on old defect sites provoked on the surface or borders of C nanotubes by aggressive chemical agencies. These aggressive interventions render an oxidised nanotube surface or even structural harm that deteriorates their outstanding electrical, mechanical, and optical belongingss significantly. Therefore, supramolecular or electrostatic functionalisations are better attacks for photovoltaic applications.Although in an initial phase, the consequences obtained up to now points out the high potency of these complexs to construct up photovoltaic devices and solar cells. hypertext transfer protocol: //www.sciencedaily.com/releases/2008/11/081104114427.htm.

-Solar cell applications:

There is an extended scope of applications where solar cells are used ;

a ) -Rural electrification:

The proviso of electricity to rural countries derives of import societal and economic benefits to remote communities throughout the universe. Power supply to remote houses or small towns, electrification of the wellness attention installations, irrigation and H2O supply and intervention are merely few illustrations of such applications.