Cu ( In , Ga ) Se 2
8 February 2017 Concentrating light in Cu ( In , Ga ) Se 2
Author Affiliations +
J. of Photonics for Energy, 7(1), 018001 (2017). doi:10.1117/1.JPE.7.018001
Light concentration has proven beneficial for solar cells, most notably for highly efficient but expensive absorber materials using high concentrations and large scale optics. Here, we investigate the light concentration for cost-efficient thin-film solar cells that show nano- or microtextured absorbers. Our absorber material of choice is Cu ( In , Ga ) Se 2 (CIGSe), which has a proven stabilized record efficiency of 22.6% and which—despite being a polycrystalline thin-film material—is very tolerant to environmental influences. Taking a nanoscale approach, we concentrate light in the CIGSe absorber layer by integrating photonic nanostructures made from dielectric materials. The dielectric nanostructures give rise to resonant modes and field localization in their vicinity. Thus, when inserted inside or adjacent to the absorber layer, absorption and efficiency enhancement are observed. In contrast to this internal absorption enhancement, external enhancement is exploited in the microscaled approach: mm-sized lenses can be used to concentrate light onto CIGSe solar cells with lateral dimensions reduced down to the micrometer range. These micro solar cells come with the benefit of improved heat dissipation compared with the large scale concentrators and promise compact high-efficiency devices. Both approaches of light concentration allow for reduction in material consumption by restricting the absorber dimension either vertically (ultrathin absorbers for dielectric nanostructures) or horizontally (microabsorbers for concentrating lenses) and have significant potential for efficiency enhancement.
© 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)
Martina Schmid, Guanchao Yin, Min Song, Shengkai Duan, Berit Heidmann, Diego Sancho-Martinez, Steven Kämmer, Tristan Köhler, Phillip Manley, Martha C. Lux-Steiner, "Concentrating light in Cu ( In , Ga ) Se 2 Journal of Photonics for Energy 7(1), 018001 (8 February 2017). Submission: Received 26 September 2016; Accepted 13 January 2017
Submission: Received 26 September 2016; Accepted 13 January 2017

Solar cells





External quantum efficiency



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