The chemical potential of radiation

Würfel, P.

doi:10.1088/0022-3719/15/18/012

Cited by 877 publications

(667 citation statements)

References 17 publications

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“…In the case of electro-luminescence the latter is often approximated in practice by the applied voltage [13].…”

Section: Chemical Potential Of Luminescent Radiationmentioning

confidence: 99%

The thermodynamics of optical étendue

Markvart¹

2007

J. Opt. A: Pure Appl. Opt.

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The concept ofétendue is applied to the propagation of luminescent radiation, and to the transformation of such radiation in absorbing and luminescent media. Central to this analysis is the notion ofétendue as a measure of the number of rays in the beam which permits the definition of entropy and transition to the formalism of statistical mechanics. When considered from the statistical viewpoint,étendue conservation along the path of a beam in clear and transparent media then implies the conservation of entropy. The changes in thermodynamic parameters of a beam upon absorption and re-emission can then be determined in terms of the corresponding changes resulting from the addition or removal of photons from the incident and emitted beam. The thermodynamic theory which follows gives the rate of entropy generation in this process. At moderate light intensities, the results resemble the thermodynamics of a two-dimensional gas. The formalism allows an extension to absorption/emission processes where a high-temperature incident light beam is transformed reversibly into low-temperature luminescent radiation, corresponding to a potential increase in the open-circuit voltage of a solar cell.

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“…In the case of electro-luminescence the latter is often approximated in practice by the applied voltage [13].…”

Section: Chemical Potential Of Luminescent Radiationmentioning

confidence: 99%

The thermodynamics of optical étendue

Markvart¹

2007

J. Opt. A: Pure Appl. Opt.

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“…and e 2 that are emitted by a surface at temperature T in a vacuum in the normal direction and per unit of solid angle are given by the generalized Planck equation [1,14]: e(s).…”

Section: Spatial/spectral Extension Of Radiationmentioning

confidence: 99%

“…Furthermore, it can be deduced from Eq. (14) that in the case of using an ideal cut-off emitter with e ce = £ gap , p b sr does not affect the system performance because the last term of Eq. (14) vanishes.…”

Section: Non-ideal Tpv Cavitymentioning

confidence: 99%

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Detailed balance analysis of solar thermophotovoltaic systems made up of single junction photovoltaic cells and broadband thermal emitters

Datas

Algora

2010

Solar Energy Materials and Solar Cells

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Keywords:Solar thermophotovoltaic system Concentration Optical cavity Spectral control Selective absorber This paper presents a detailed balance analysis of a solar thermophotovoltaic system comprising an optical concentrator, a cut-off broad band absorber and emitter, and single junction photovoltaic cells working at the radiative limit with an integrated back-side reflector in a configuration in which the cells enclose the emitter to form an optical cavity. The analysis includes the effect of multiple variables on the system performance (efficiency and electrical power density), such as the concentration factor, the emitter-to-absorber area ratio, the absorber and emitter cut-off energies, the semiconductor band-gap energy and the voltage of the cells. Furthermore, the effect of optical losses within the cavity such as those attributed to a back-side reflector with reflectivity lower than one or to a semi-open optical cavity is also included. One of our main conclusions is that for a planar system configuration (the emitter, the cells and the absorber have the same area) the combination of low concentration and a spectrally selective absorber provides the highest system efficiencies. The efficiency limit of this kind of systems is 45.3%, which exceeds the Shockley-Queisser limit of 40.8% (obtained for a single junction solar cell, directly illuminated by the sun, working under maximum concentration and with an optimized band-gap). This system also has the great benefit of requiring a very low concentration factor of 4.4 suns.

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“…We also need the recombination current, which-in the SQ limit-only depends on the photon flux emitted by the solar cell. Since the SQ limit assumes perfect transport of carriers, i.e., flat quasiFermi levels, the application of a voltage V to the junction of the solar cell leads to an excess emission of photons given by 53 em ͑E͒ = a͑E͒ bb ͑E͒ ͫ expͩ qV kT ͪ−1ͬ.…”

Section: B Shockley-queisser Limit-optical Calculationsmentioning

confidence: 99%

Efficiency limits of Si/SiO2 quantum well solar cells from first-principles calculations

Kirchartz

Seino

Wagner

et al. 2009

Journal of Applied Physics

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In order to investigate the applicability of new photovoltaic absorber materials, we show how to use first-principles calculations combined with device simulations to determine the efficiency limits of solar cells made from SiO2/Si superlattices and from coaxial ZnO/ZnS nanowires. Efficiency limits are calculated for ideal systems according to the Shockley–Queisser theory but also for more realistic devices with finite mobilities, nonradiative lifetimes, and absorption coefficients. Thereby, we identify the critical values for mobility and lifetime that are required for efficient single junction as well as tandem solar cells.

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The chemical potential of radiation

Cited by 877 publications

References 17 publications

The thermodynamics of optical étendue

The thermodynamics of optical étendue

Detailed balance analysis of solar thermophotovoltaic systems made up of single junction photovoltaic cells and broadband thermal emitters

Efficiency limits of Si/SiO2 quantum well solar cells from first-principles calculations

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