One Lateral Spectrum Splitting Concentrator Photovoltaic architecture: Measurements of current assemblies and analysis of pathways to 40% efficient modules

Abstract

Lateral Spectrum Splitting Concentrator Photovoltaics (LSSCPV) systems are being developed for high energy conversion efficiency. LSSCPV can concentrate available sunlight and laterally split a single beam into bands with different spectra, for absorption by solar cells with matched band gaps. Assemblies of an LSSCPV architecture including four p-n junctions were constructed, and tested by two institutes independently. One of the assemblies demonstrated verified module efficiency of 36.7%. In addition to the whole assembly efficiency, measurement methodology and testing procedure were proposed to assess the performance of each individual component in the system. The comparisons between the expected component efficiencies and the actually measured values, together with the comparisons between the independent assembly efficiency measurements by two organizations helped identify pathways to module efficiency greater than 40%.

Overview of Concentrated Photovoltaic (CPV) Cells

“…A typical cell composition for a three-cell system is GaInP (31.7%), GaInAs/GaInAs (bottom filtered by Si) (6.2%), and silicon (filtered by GaAs) 5%. The total efficiency is 42.9% [10].…”

“…Further research suggests the use of InGaN for increased bandwidth (0.7 -2.4 ev) collection and improved efficiency [10]. Because the cells are separate from each other the constraints of current and lattice matching do not apply.…”

“…The system is portable and light therefore suitable for rooftop. The best efficiency achieved is 42.9% at 20 suns with 93% optical efficiency [10]. A typical cell composition for a three-cell system is GaInP (31.7%), GaInAs/GaInAs (bottom filtered by Si) (6.2%), and silicon (filtered by GaAs) 5%.…”

“…Con- Figure 4. Lateral spectrum splitting concentrator photovoltaic cell [10]. centration in the excess of 1000 suns gives the highly concentrated photovoltaics (HCPV) [13].…”

An optical arrangement for boosting the efficiency of a system containing a GaAs solar cell

“…Since then, many designs have been proposed [1, 8,9]. Outdoors system efficiencies of 30.8 % and 38.9 % have been measured on systems with three and four solar cells, respectively, under real outdoor conditions [10,11]. The main advantages of this approach are:…”