SKM 2023 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 6: Perovskite and photovoltaics I (joint session HL/CPP)

CPP 6.5: Talk

Monday, March 27, 2023, 10:30–10:45, JAN 0027

Photon Management for Ultrathin Solar Cells: Enabling Waveguide Modes by Structured Back Contact — •Merve Demir, Thomas Schneider, Torsten Hölscher, Heiko Kempa, and Roland Scheer — Martin-Luther-Universität Halle-Wittenberg, Germany

The recent research based on Cu(In,Ga)Se2 (CIGSe) solar cells is focused on thinning down the absorber layer to enable less material consumption and cost effective large scale production. However, having ultra-thin CIGSe solar cells with absorber layer thickness in sub-micron level brings the cost of limited absorption of solar spectra and hence leads to lower energy conversion efficiencies. This problem can be overcome by the cell architecture including functional back contact elements for the enhancement of optical absorption. In this contribution, ultrathin CIGSe solar cells with 500 nm thick absorber layer were combined with nano-textured SiO2 back contacts together with aluminum back mirror. With this cell design, it is aimed to have increased power conversion efficiency for ultra-thin CIGSe solar cells due to enhanced absorption of long wavelength region photons. The solar cell parameters were extracted and compared with the conventional CIGSe back contact, flat molybdenum, to reveal the effects of functional back contact. The experimental findings on quantum efficiency measurements prove the positive effects of having highly reflective and textured back contact. Furthermore, the growth of CIGSe on textured substrates was examined throughout cross section cuts by scanning electron microscopy and energy dispersive X-ray diffraction.