# Thermodynamic efficiency limit > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Thermodynamic_efficiency_limit > Markdown URL: https://mediated.wiki/source/Thermodynamic_efficiency_limit.md > Source: https://en.wikipedia.org/wiki/Thermodynamic_efficiency_limit > Source revision: 1316177472 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) {{Short description|Maximum possible efficiency of electrical power from sunlight}}The '''thermodynamic efficiency limit''' is the absolute maximum theoretically possible [conversion efficiency](/source/conversion_efficiency) of sunlight to [electricity](/source/electricity). Its value is about 86%, which is the [Chambadal-Novikov efficiency](/source/Endoreversible_thermodynamics), an approximation related to the [Carnot limit](/source/Carnot_cycle), based on the temperature of the [photon](/source/photon)s emitted by the Sun's surface.{{Citation needed|date=December 2019|reason=removed citation to predatory publisher content}} == Effect of band gap energy == [Solar cells](/source/Solar_cells) operate as [quantum](/source/quantum) [energy conversion device](/source/energy_conversion_device)s, and are therefore subject to the thermodynamic efficiency limit. [Photons](/source/Photons) with an energy below the [band gap](/source/band_gap) of the absorber material cannot generate an [electron-hole pair](/source/electron-hole_pair), and so their energy is not converted to useful output and only generates heat if absorbed. For photons with an energy above the band gap energy, only a fraction of the energy above the band gap can be converted to useful output. When a photon of greater energy is absorbed, the excess energy above the band gap is converted to [kinetic energy](/source/kinetic_energy) of the [carrier recombination](/source/carrier_recombination). The excess kinetic energy is converted to heat through phonon interactions as the kinetic energy of the carriers slows to equilibrium velocity. Hence, the solar energy cannot be converted to electricity beyond a certain limit.{{cite web|url=http://www.me.berkeley.edu/~ndhillon/Publications/PDF/reports/6_organic_solar_cells.pdf|title= Nanostructured Organic Solar Cell|publisher=me.berkeley.edu|access-date=2011-07-22}} Solar cells with multiple band gap absorber materials improve efficiency by dividing the solar spectrum into smaller bins where the thermodynamic efficiency limit is higher for each bin.{{Cite journal|title=Limiting efficiencies for multiple energy-gap quantum devices| author=Cheng-Hsiao Wu and Richard Williams|doi=10.1063/1.331859|journal=J. Appl. Phys.|volume=54| issue=11|page=6721 |year=1983| bibcode=1983JAP....54.6721W}} The thermodynamic limits of such cells (also called multi-junction cells, or tandem cells) can be analyzed using and online simulator in nanoHUB.{{Cite journal|url=https://nanohub.org/tools/pvlimits|title=nanoHUB.org – Resources: PVLimits: PV thermodynamic limit calculator|website=nanohub.org|date=20 March 2016 |access-date=2016-06-12 |last1=Khan |first1=Mohammad Ryyan |last2=Jin |first2=Xin |last3=Alam |first3=Muhammad A. }}{{cite web|url=https://www.solarweasel.com/de/solar-rechner/|title=Solar Yield calculator|date=14 October 2022|language=de}} == Efficiency limits for different solar cell technologies == Thermodynamic efficiency limits for different solar cell technologies are as follows: * Single junctions ≈ 33% * 3-cell stacks and impure PVs ≈ 50% * Hot carrier- or impact ionization-based devices ≈ 54-68% * Commercial modules are ≈ 12-21% * Solar cell with an upconverter for operation in the [AM1.5](/source/Air_mass_(solar_energy)) spectrum and with a 2eV bandgap ≈ 50.7%{{cite web|url=http://gcep.stanford.edu/pdfs/assessments/solar_assessment.pdf|title= An Assessment of Solar Energy Conversion Technologies and Research Opportunities|publisher=gcep.stanford.edu|access-date=2011-07-22}} == Thermodynamic efficiency limit for excitonic solar cells == [[File:ShockleyQueisserFullCurve.svg|thumb|The [Shockley-Queisser limit](/source/Shockley-Queisser_limit) for the efficiency of a single-junction solar cell under unconcentrated sunlight. This calculated curve uses actual solar spectrum data, and therefore the curve is wiggly from IR absorption bands in the atmosphere. This efficiency limit of about 34% can be exceeded by [multijunction solar cell](/source/multijunction_solar_cell)s.]] Excitonic solar cells generates free charge by bound and intermediate exciton states unlike inorganic and [crystalline](/source/Polycrystalline_silicon_photovoltaics) solar cells. The efficiency of the excitonic solar cells and inorganic solar cells (with less exciton-binding energy){{cite journal|last1=Giebink|first1=Noel C.|last2=Wiederrecht|first2=Gary P.|last3=Wasielewski|first3=Michael R.|last4=Forrest|first4=Stephen R.|date=May 2011|title=Thermodynamic efficiency limit of excitonic solar cells|journal= Physical Review B|volume=83|issue=19|article-number=195326|doi=10.1103/PhysRevB.83.195326|bibcode=2011PhRvB..83s5326G|url=https://zenodo.org/record/1233759}} cannot go beyond 31% as explained by Shockley and Queisser.{{cite journal|last1=Shockley|first1=William|last2=Queisser|first2=Hans J.|year=1961|title=Detailed Balance Limit of Efficiency of p-n Junction Solar Cells|journal=Journal of Applied Physics|volume=32|issue=3|pages=510–519|publisher=The American Institute of Physics|doi=10.1063/1.1736034|url=http://jap.aip.org/resource/1/japiau/v32/i3/p510_s1?isAuthorized=no|access-date=2011-07-22|bibcode=1961JAP....32..510S|url-access=subscription}} == Thermodynamic efficiency limits with carrier multiplication == [Carrier multiplication](/source/Carrier_multiplication) facilitates multiple [electron-hole pair](/source/electron-hole_pair) generation for each photon absorbed. Efficiency limits for photovoltaic cells can be theoretically higher considering thermodynamic effects. For a solar cell powered by the Sun's unconcentrated [black-body radiation](/source/black-body_radiation), the theoretical maximum efficiency is 43% whereas for a solar cell powered by the Sun's full concentrated radiation, the efficiency limit is up to 85%. These high values of efficiencies are possible only when the solar cells use [radiative recombination](/source/radiative_recombination) and carrier multiplication.{{cite journal|last1=Brendel|first1=Rolf|last2=Werner|first2=Jürgen H.|last3= Queisser|first3=Hans J.|year=1996|title=Thermodynamic efficiency limits for semiconductor solar cells with carrier multiplication|journal=Solar Energy Materials and Solar Cells|volume=41-42|pages=419–425|publisher=Elsevier|doi=10.1016/0927-0248(95)00125-5|issn=0927-0248|url=http://www.mendeley.com/research/thermodynamic-efficiency-limits-semiconductor-solar-cells-carrier-multiplication/|access-date=2011-07-22|url-access=subscription}} == See also == {{Portal|Renewable energy|Energy}} * [Quantum efficiency of a solar cell](/source/Quantum_efficiency_of_a_solar_cell) * [Energy conversion efficiency](/source/Energy_conversion_efficiency) * [Photoelectric effect](/source/Photoelectric_effect) * [Solar cell efficiency](/source/Solar_cell_efficiency) == References == {{Reflist}} {{Photovoltaics}} Category:Photovoltaics Category:Solar cells Category:Thermodynamic processes --- Adapted from the Wikipedia article [Thermodynamic efficiency limit](https://en.wikipedia.org/wiki/Thermodynamic_efficiency_limit) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Thermodynamic_efficiency_limit?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.