Limiting efficiencies of ideal single and multiple energy gap terrestrial solar cells
Abstract
The maximum efficiencies of ideal solar cells are calculated for both single and multiple energy gap cells using a standard air mass 1.5 terrestrial solar spectrum. The calculations of efficiency are made by a simple graphical method, which clearly exhibits the contributions of the various intrinsic losses. The maximum efficiency, at a concentration of 1 sun, is 31%. At a concentration of 1000 suns with the cell at 300 K, the maximum efficiencies are 37, 50, 56, and 72% for cells with 1, 2, 3, and 36 energy gaps, respectively. The value of 72% is less than the limit of 93% imposed by thermodynamics for the conversion of direct solar radiation into work. Ideal multiple energy gap solar cells fall below the thermodynamic limit because of emission of light from the forwardbiased pn junctions. The light is radiated at all angles and causes an entropy increase as well as an energy loss.
 Publication:

Journal of Applied Physics
 Pub Date:
 August 1980
 DOI:
 10.1063/1.328272
 Bibcode:
 1980JAP....51.4494H
 Keywords:

 Energy Conversion Efficiency;
 Energy Gaps (Solid State);
 Semiconductor Devices;
 Solar Cells;
 Energy Technology;
 Photons;
 Spectral Energy Distribution;
 Thermodynamic Properties;
 Energy Production and Conversion;
 84.60.Jt;
 85.30.De;
 Photoelectric conversion: solar cells and arrays;
 Semiconductordevice characterization design and modeling