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Transient Analysis of Luminescent Coupling Effects in Multi-junction Solar Cells

 
: Tayagaki, T.; Reichmuth, K.; Helmers, H.; Siefer, G.

:

Journal of applied physics 124 (2018), No.18, Art. 183103, 9 pp.
ISSN: 0021-8979
ISSN: 1089-7550
English
Journal Article
Fraunhofer ISE ()
Photovoltaik; III-V und Konzentrator-Photovoltaik; Power-by-Light

Abstract
We investigate the luminescent coupling (LC) effects in a four-junction GaInP/GaAs//GaInAsP/GaInAs concentrator solar cell based on transient open-circuit voltage (Voc) measurements under monochromatic illumination. Photocurrent generation in the non-absorbing GaInAs bottom subcell due to LC from upper subcells shows superlinear behavior with increasing light intensity. Along with this, a Voc enhancement is observed and quantified for illumination intensities that span almost six orders of magnitude. The Voc increase is explained and studied using a series-connected diode model including subcell shunt resistances, capacitances, and LC effects. The impact of unilluminated subcells on the subcell Voc determination is discussed for multi-junction solar cells. Finally, in the analysis of the LC generated photocurrent, namely, the coupling factor from the GaInAsP to the non-absorbing GaInAs subcell, a characteristic dependency on bias voltage is shown and explained by a result of competing photo- and electroluminescence mechanisms.

: http://publica.fraunhofer.de/documents/N-548728.html