skip to main content

SciTech ConnectSciTech Connect

Title: Effects of angular confinement and concentration to realistic solar cells

In standard solar cells, light impinges under a very small angular range, whereas the solar cell emits light into the whole half space. Due to this expansion of etendué, entropy is generated, which limits the maximal efficiency of solar cells. This limit can be overcome by either increasing the angle of incidence by concentration or by decreasing the angle of emission by an angularly confining element or by a combination of both. In an ideal solar cell with radiative recombination as the only loss mechanism, angular confinement and concentration are thermodynamically equivalent. It is shown that concentration in a device, where non-radiative losses such as Shockley-Read-Hall and Auger recombination are considered, is not equivalent to angular confinement. As soon as non-radiative losses are considered, the gain in efficiency due to angular confinement drops significantly in contrast to the gain caused by concentration. With the help of detailed balance calculations, it is furthermore shown that angular confinement can help to increase the efficiency of solar cells under concentrated sunlight even if no measurable gain is expected for the solar cell under 1-sun-illumination. Our analysis predicts a relative gain of 3.14% relative in efficiency for a realistic solar cell with a concentrationmore » factor of 500.« less
Authors:
; ;  [1] ;  [2]
  1. Fraunhofer Institute for Solar Energy Systems, 79110 Freiburg (Germany)
  2. Laboratory for Optoelectronics, Institute of Microsystems Engineering (IMTEK), Albert-Ludwigs-University of Freiburg, 79110 Freiburg (Germany)
Publication Date:
OSTI Identifier:
22412965
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 3; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; AUGER EFFECT; CONCENTRATION RATIO; EFFICIENCY; EMISSION; ENTROPY; GAIN; ILLUMINANCE; INCIDENCE ANGLE; RECOMBINATION; SOLAR CELLS; VISIBLE RADIATION