Impact of optically nonuniform luminescence coupling effect to the limiting cell conversion efficiency in InGaP/GaAs/Ge triple junction solar cell

Abstract

Abstract. The impact of nonuniform spatial distribution of the luminescence coupling (LC) effect to the limiting cell conversion efficiency of multijunction solar cells (MJSCs) has been investigated. For this purpose, the laser beam induced current distribution maps of the limiting bottom cell have been acquired experimentally under varying middle-to-bottom cell LC efficiencies. The minimum and the maximum LC efficiencies demonstrated were 8.5% and 69%, respectively. To further analyze the measurement results, a quasi-two-dimensional simulation model considering the spatially nonuniform nature of the LC effect has been developed. A good agreement between the simulation and the measurement results suggests that the nonuniform LC current distribution is induced by optical phenomena such as photon escape and internal reflection. This nonuniformity then causes the absolute conversion efficiency of the limiting cell to be reduced by 1.35% at maximum LC efficiency. This reduction, when suppressed, can yield higher limiting cell conversion efficiency, which in turn may improve the overall MJSC conversion efficiency.

Luminescent coupling effect in InGaP/GaAs/InGaAs inverted metamorphic triple-junction solar cell

“…(1), which is obtained as 0.21. This nonuniformity in the bottom cell LC current is attributed to the perimeter recombination 32 . Moreover, the nonuniform spatial distribution has resulted in a decrease in the overall current value.…”

“…This nonuniformity in the bottom cell LC current is attributed to the perimeter recombination. 32 Moreover, the nonuniform spatial distribution has resulted in a decrease in the overall current value. This finding highlights the potential for Thakur, Yu Jeco-Espaldon and Okada: Luminescent coupling effect.…”

Current transport efficiency analysis of multijunction solar cells by luminescence imaging

“…A reciprocity relation has been derived, showing that this ratio is equivalent to the third member of Equation , ie, the ratio of the voltage variation δV ( x , y ) at the position ( x , y ), induced by a voltage variation δV T at the terminal. The transport efficiency can be measured, in the sense of the second term of Equation , with a light beam induced current (LBIC) setup, which excites the cell locally and scans the surface . However, scanning the surface can be time consuming, especially when large surfaces are analyzed, or when high resolution is required.…”

“…The transport efficiency can be measured, in the sense of the second term of Equation (1), with a light beam induced current (LBIC) setup, which excites the cell locally and scans the surface. 3,4 However, scanning the surface can be time consuming, especially when large surfaces are analyzed, or when high resolution is required. An alternative approach using luminescence measurement, taking advantage of the reciprocity relation, can be used to obtain the transport efficiency.…”