Determination of subcell I–V characteristics of multijunction solar cells using optical coupling. (18th December 2015)

• Record Type: Journal Article
• Authors: Nesswetter, Helmut; Jost, Norman R.; Lugli, Paolo; Bett, Andreas W.; Zimmermann, Claus G.
• Is Part Of: Progress in photovoltaics. Volume 24:Number 6(2016)
• Page Start: 760
• Page End: 773
• Publication Date: 2015-12-18
• Subjects: optical coupling -- multijunction solar cell -- characterization -- subcell diode parameters; Solar cells -- Periodicals; Photovoltaic cells -- Periodicals; Solar power plants -- Periodicals; 621.31245
• DOI: 10.1002/pip.2722
• Languages: English
• ISSNs: 1062-7995

Abstract

Abstract: A method for the determination of the subcell I–V characteristics of multijunction solar cells in the presence of optical coupling is presented and applied to a Ga0.50 In0.50 P/Ga0.99 In0.01 As/Ge triple‐junction solar cell. Each of the subcells is described by a two‐diode model and can be illuminated by a narrowband light source externally. Optical coupling is then used explicitly to generate current in one subcell, which is not illuminated externally. This approach yields the magnitude of optical coupling and a relationship between the two diode parameters of each subcell. The remaining cell parameters are determined with the help of pulsed illumination. In this fashion, the open circuit voltage of individual subcells is accessible, despite the fact that not all junctions are illuminated. Copyright © 2015 John Wiley & Sons, Ltd. Abstract : Using steady state monochromatic illumination of single subcells and exploiting optical coupling in the one subcell not illuminated externally, the ratio of the two diode parameter of each subcell can be determined. Using pulsed illumination, the open circuit voltage of the subcells is accessible as well and thus both diode parameters can be determined in absolute terms. With this methodology, the I‐V curves of the cell under different illumination conditions as well as its dark I‐V curve can be reproduced.