Lecture G. Bauer
|10 June 2011||FWN-Building 5118.-156, Nijenborgh 4, 9747 AG, Groningen|
|Speaker:||Prof. Dr. G. Bauer|
|Affiliation:||Oldenburg University, Germany|
|Title:||What do we learn in photovoltaics from luminescence; the Shockley-Queisser limit and beyond|
|Date:||Fri Jun 10, 2011|
|Telephone:||+31 50 363 5553 / 8750 (secr.)|
The maximum efficiency of solar light conversion for a single homogeneous absorber is formulated via the Shockley-Queisser-ansatz, in which the stationary state in a electronic two-level system under illumination is established by the balance of absorption and emission of photons (radiative limit).
Thus the light emitted from photo excited matter by spectral shape and total photon flux reflects the spectral absorption/emissivity, the temperature and the chemical potential of the photons µγ, being identical with the chemical potential of the electron-hole ensemble µnp. Even with additional non-radiative transitions the emitted fluorescence quantifies the photo excited state and allows for the determination of µnp, announcing the maximum voltage achievable in a diode.
Respective experimental result of luminescence from c-Si, Cu(In,Ga)(S,Se)2, CdTe, and from “arrangements” of approaches for exceeding the Shockley-Queisser limit demonstrate the general suitability of luminescence analyses for the identification of losses in quantum solar energy conversion.
|Last modified:||22 October 2012 2.30 p.m.|