What is Photovoltaics: Definition and 18 Discussions

Photovoltaics (PV) is the conversion of light into electricity using semiconducting materials that exhibit the photovoltaic effect, a phenomenon studied in physics, photochemistry, and electrochemistry. The photovoltaic effect is commercially utilized for electricity generation and as photosensors.
A photovoltaic system employs solar modules, each comprising a number of solar cells, which generate electrical power. PV installations may be ground-mounted, rooftop-mounted, wall-mounted or floating. The mount may be fixed or use a solar tracker to follow the sun across the sky.
Some hope that photovoltaic technology will produce enough affordable sustainable energy to help mitigate global warming caused by CO2. Solar PV has specific advantages as an energy source: once installed, its operation generates no pollution and no greenhouse gas emissions, it shows simple scalability in respect of power needs and silicon has large availability in the Earth's crust, although other materials required in PV system manufacture such as silver will eventually constrain further growth in the technology. Other major constraints identified are competition for land use and lack of labor in making funding applications. The use of PV as a main source requires energy storage systems or global distribution by high-voltage direct current power lines causing additional costs, and also has a number of other specific disadvantages such as unstable power generation and the requirement for power companies to compensate for too much solar power in the supply mix by having more reliable conventional power supplies in order to regulate demand peaks and potential undersupply. Production and installation does cause pollution and greenhouse gas emissions and there are no viable systems for recycling the panels once they are at the end of their lifespan after 10 to 30 years.
Photovoltaic systems have long been used in specialized applications as stand-alone installations and grid-connected PV systems have been in use since the 1990s. Photovoltaic modules were first mass-produced in 2000, when German environmentalists and the Eurosolar organization received government funding for a ten thousand roof program.Decreasing costs has allowed PV to grow as an energy source. This has been partially driven by massive Chinese government investment in developing solar production capacity since 2000, and achieving economies of scale. Much of the price of production is from the key component polysilicon, and most of the world supply is produced in China, especially in Xinjiang. Beside the subsidies, the low prices of solar panels in the 2010s has been achieved through the low price of energy from coal and cheap labour costs in Xinjiang, as well as improvements in manufacturing technology and efficiency. Advances in technology and increased manufacturing scale have also increased the efficiency of photovoltaic installations. Net metering and financial incentives, such as preferential feed-in tariffs for solar-generated electricity, have supported solar PV installations in many countries. Panel prices dropped by a factor of 4 between 2004 and 2011. Module prices dropped 90% of over the 2010s, but began increasing sharply in 2021.In 2019, worldwide installed PV capacity increased to more than 635 gigawatts (GW) covering approximately two percent of global electricity demand. After hydro and wind powers, PV is the third renewable energy source in terms of global capacity. In 2019 the International Energy Agency expected a growth by 700 - 880 GW from 2019 to 2024. In some instances, PV has offered the cheapest source of electrical power in regions with a high solar potential, with a bid for pricing as low as 0.01567 US$/kWh in Qatar in 2020.

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  1. J3J33J333

    I Infrared Photovoltaics: Powering Ham Radios & Cooling Earth?

    Can you use infrared solar panels to power a ham radio and turn infrared into radio waves to get the energy past the green house gases? Because infrared gets reflected by greenhouse gases and warms the Earth while radio waves don't. Would this help cool the Earth?
  2. Mayan Fung

    I Recombination and open-circuit voltage in solar cells

    From the ideal diode model, we can derive the open-circuit voltage (Voc) as: $$ V_{oc} = \frac{nkT}{q} ln(\frac{I_L}{I_0} + 1) $$ where ##I_0## is the dark saturation current and ##I_L## is the light generated current. From the model, if the recombination rate increases, the dark saturation...
  3. D

    Photovoltaics and time near a black hole (as a key story element)

    I'm a physics student and science fiction writer, and I've never been to this section of PF before! But I have an idea I think is cool for a novel or short story and I'd like some input on the physics involved. As I'm not overly worried about this idea being stolen I'm going to provide a short...
  4. V

    A Photovoltaic Effect in CdS or CdSe

    I have a somewhat different question to the usual sort asked. In the literature on photovoltaics numerous authors, both academic and popular refer to an Audobert and Stora who in 1932 observed the photovoltaic effect in either CdS or CdSe, depending on the author, however no citation is given...
  5. maverick_starstrider

    I Transport in PV Cells (and pn diodes)

    Hi, I'm having some trouble wrapping my head around some of the concepts and language of charge transport in Photovoltaic cells (and thus pn-diodes). My biggest problem is understanding the role played by the emitter region vs. the depletion region. In a typical PV cell the front emitter...
  6. P

    Solar photovoltaics: - What happens to the lost energy?

    I have a very simple question about solar photovoltaic systems. We all know that they have limited efficiency. Suppose there is a module that is 10% efficient i.e. it can convert 10% of sunlight falling onto it into electricity. I just want to know what will happen to the rest 90%? I mean do...
  7. N

    Quantum Photovoltaics and solar energy

    i want a list of books related to photovoltaics specifically the ones related to the mechanism
  8. Corwin_S

    Maximum Built-In Voltage of a PN junction

    Hi, I'm familiar with the expression for calculating the built-in voltage of a p-n junction. How can I find the maximum built-in voltage before the semiconductor becomes degenerate (i.e., a bad metal) if I only know the material and the intrinsic carrier concentration at a given temperature...
  9. W

    Can ocean wave energy be harnessed with low-cost technology?

    Greetings from Costa Rica. I have an M.A. in Physical Science and a B.S. in Physics from San Diego State University, California, USA. For my master's thesis, I built and tested a prototype "Ocean Wave Driven Air Pump" in the Scripps Oceanographic Institute in La Jolla, CA in 1970-1971. The test...
  10. mnmman

    Concentrated Photovoltaics, Parabolic Mirrors

    The idea of a parabolic mirror to focus light onto a small solar panel popped into my mind the other day. I searched Google and this is about the best thing I found- http://www.greenrhinoenergy.com/solar/technologies/pv_concentration.php and...
  11. C

    Solar efficiencies of photovoltaics in relation to the band gap energies?

    I'm reading a paper on photovoltaic hydrogen production and the author claims that for reasonable solar efficiencies the band gap must be less than 2.0eV. This I understand. My question is how will it effect the photon absorption if the band gap is much smaller. Say the band gap energy is...
  12. E

    Photovoltaics: Does a Solar Cell Need Current to Work?

    Hello everyone ! I have a very basic question about phovoltaics: does a photovoltaic solar cell need to be current to work ? I mean it sounds stupid since we use solar cell to produce current and not the opposite... The fact is I do not really understand how the cell produces current, I was...
  13. A

    Photovoltaics, Electric motors ,Solar energy. Should i go for EE?

    Hello. I want to work with Photovoltaics and with the renewable industry. Electric motors, boats, cars. Is EE a good choice? I was thinking first in ME but looks like you see more of solar energy in EE. Please i need urgent advice i only left like 2 moths to make a choice.
  14. S

    Is the Photoelectric Effect an Ideal Heat Sink for Photovoltaic Cells?

    Hey all, First off, thks to everyone here on physicsforums, this is such a great resource for anything physics-related. I was thinking today about the photoelectric effect, and a scenario popped into my head which seemed counter-intuitive. Please correct me if I'm wrong, it's been a while...
  15. M

    Ideas for a Senior Project in Photovoltaics

    Hello, I am trying to come up with a good senior project for my physics degree. I am really interested in PV and I have spent a lot of time researching the literature and whatnot but haven't been able to come up with an original idea for a project. My first idea was improving the efficiency of...
  16. C

    What is the future for photovoltaics?

    Yes, I was wondering if anyone was, perhaps familiar with the industry of photovoltaic cells and how that industry is maturing. In particular, how efficient are the best cells available today. I would guess its measured in something like Watts/Surface Area, or some statistic like that...
  17. C

    Exploring CadTel Solar Cells and Photovoltaics

    Hey I got the oppurtunity to work in a research lab that focused on CadTel solar cells this summer and learned a fair deal about them, I also intend to take a class on Photovoltaics in the spring but I was just wondering how people feel about the cadmium in cadtel and would love some more...
  18. P

    Photovoltaics film solar cell technology

    Hey all, New guy on the site. Just to start off, I'm 15 year old who enjoys reading (mainly physics). Now, as many may already know, current crystaline silicon has been proven to have a total efficiency of 25%. Some companies have even quit on their thin film solar cell technology due...